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RSS2004 Vol. 16, No. 02
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2004,
16.
Abstract:
As the fundament of wire array Z pinch experiment, the design of the load is very important. In this paper, the slug model is introduced. On the basis of analyzing the principle of the model, the wire array experiment results on Saturn generator are used to test the model and the program. The calculation results prove the program is of better reliability and practicality. After analyzing Qiangguang I generator's circuit and getting the electric parameters of the generator, the wire array experiments on the Qiangguang I are simulated by the slug model. The calculated load current results well agree with the experiment results and the errors are within 5%. This indicates that the slug model will be helpful to the design and the experiments on Qiangguang I generator.
As the fundament of wire array Z pinch experiment, the design of the load is very important. In this paper, the slug model is introduced. On the basis of analyzing the principle of the model, the wire array experiment results on Saturn generator are used to test the model and the program. The calculation results prove the program is of better reliability and practicality. After analyzing Qiangguang I generator's circuit and getting the electric parameters of the generator, the wire array experiments on the Qiangguang I are simulated by the slug model. The calculated load current results well agree with the experiment results and the errors are within 5%. This indicates that the slug model will be helpful to the design and the experiments on Qiangguang I generator.
Study on a 20GW inductive energy storage pulsed power conditioning device with a low resistance load
2004,
16.
Abstract:
The computation is carried out for the inductive energy storage pulsed power conditioning system with an exploding wire opening switch. On this basis,a smallsized inductive energy storage pulsed power conditioning device which outputs peak power of more than 20GW, is developed and tested. When energized by a 4μF/100kV capacitor bank operating at above 64kV, a pulse voltage and pulse current in excess of 400kV and 60kA respectively with over 100ns duration is obtained on a 6～8Ω load. The peak power exceeds 2０GW.the efficiency of energy transfer is more than 30%．
The computation is carried out for the inductive energy storage pulsed power conditioning system with an exploding wire opening switch. On this basis,a smallsized inductive energy storage pulsed power conditioning device which outputs peak power of more than 20GW, is developed and tested. When energized by a 4μF/100kV capacitor bank operating at above 64kV, a pulse voltage and pulse current in excess of 400kV and 60kA respectively with over 100ns duration is obtained on a 6～8Ω load. The peak power exceeds 2０GW.the efficiency of energy transfer is more than 30%．
2004,
16.
Abstract:
Recrystallization of irradiationinduced amorphous TiNiCu alloys has been investigated by means of the in situ transmission electron microscopy (TEM). TiNiCu shape memory alloy samples were amorphized by 400keV Xe+ ions at room temperature using IVEMTandem Facility at Argonne National Laboratory. The recovery process of amorphization was observed upon annealing from room temperature to 750℃ at a rate of 10℃ /min by in situ TEM. The recrystallization started when annealing at 280℃ for 10 min and the diffraction spots appeared around the amorphous rings. The polycrystalline rings started to form at 550℃ and the recrystallization basically finished at 750℃. The polycrystalline rings are indexed to TiNiCu SMAs. The microstructure after the recrystallization is different from that of th
Recrystallization of irradiationinduced amorphous TiNiCu alloys has been investigated by means of the in situ transmission electron microscopy (TEM). TiNiCu shape memory alloy samples were amorphized by 400keV Xe+ ions at room temperature using IVEMTandem Facility at Argonne National Laboratory. The recovery process of amorphization was observed upon annealing from room temperature to 750℃ at a rate of 10℃ /min by in situ TEM. The recrystallization started when annealing at 280℃ for 10 min and the diffraction spots appeared around the amorphous rings. The polycrystalline rings started to form at 550℃ and the recrystallization basically finished at 750℃. The polycrystalline rings are indexed to TiNiCu SMAs. The microstructure after the recrystallization is different from that of th
2004,
16.
Abstract:
Beam physics is a subject which studies the features of the beam particles transmission in electromagnetic field. It includes beam focusing, shaping and interaction with other particles. With the upgrade of beam energy and luminosity, some quantum aspects of beam particles, such as quantum effect of beam halo and spin effect on beam transport etc., seem important. Recently some accelerator physicists paid more attention on this field and named it as Quantum Beam Physics. In this paper, two different quantun methods are introduced and compared with the classical physical method.
Beam physics is a subject which studies the features of the beam particles transmission in electromagnetic field. It includes beam focusing, shaping and interaction with other particles. With the upgrade of beam energy and luminosity, some quantum aspects of beam particles, such as quantum effect of beam halo and spin effect on beam transport etc., seem important. Recently some accelerator physicists paid more attention on this field and named it as Quantum Beam Physics. In this paper, two different quantun methods are introduced and compared with the classical physical method.
2004,
16.
Abstract:
The causes of prepulse origin in pulse power machine especially in Blumlein pulser are analyzed in this paper. A method that can reduce the prepulse by an inductance between Marx and zero voltage node has been presented while a calculation example used Pspice is provided. The prepulse switches can been used to reduce the prepulse effects in many fields. The prepulse requests for wire arrays in Zpinch experiments are analyzed and explained by means of specific reaction quantity and vaporization heat, the results of the calculations are similar. In fact, the results of experiments indicate that the energy deposited in the wires is sufficient to bring the aluminicom wires to partial or total vaporization. Because the value of prepulse current is larger than that of calculation, this indicat
The causes of prepulse origin in pulse power machine especially in Blumlein pulser are analyzed in this paper. A method that can reduce the prepulse by an inductance between Marx and zero voltage node has been presented while a calculation example used Pspice is provided. The prepulse switches can been used to reduce the prepulse effects in many fields. The prepulse requests for wire arrays in Zpinch experiments are analyzed and explained by means of specific reaction quantity and vaporization heat, the results of the calculations are similar. In fact, the results of experiments indicate that the energy deposited in the wires is sufficient to bring the aluminicom wires to partial or total vaporization. Because the value of prepulse current is larger than that of calculation, this indicat
2004,
16.
Abstract:
During the past year, several measures have been tried to improve the stability of injected beam at HLS (Hefei Light Source), which has newly upgraded its injection system. To overcome the evident residual betatron oscillation, one specific betatronoscillation suppressor circuitry is accomplished to take it under control. Means to excite and damp beam motions has been suggested, as well as a PLL circuit in plan to track the variation of tune under various machine states. In addition, works as improving the performance of early version of turnbyturn system and rebuilding the software kit to make it a reliable instrumentation for beam nonlinear dynamics study and machine state monitoring.
During the past year, several measures have been tried to improve the stability of injected beam at HLS (Hefei Light Source), which has newly upgraded its injection system. To overcome the evident residual betatron oscillation, one specific betatronoscillation suppressor circuitry is accomplished to take it under control. Means to excite and damp beam motions has been suggested, as well as a PLL circuit in plan to track the variation of tune under various machine states. In addition, works as improving the performance of early version of turnbyturn system and rebuilding the software kit to make it a reliable instrumentation for beam nonlinear dynamics study and machine state monitoring.
2004,
16.
Abstract:
Surface layer temperature distribution of electrode was analyzed based on the equation of heat conduction. The parameters of arc and electrode material that influence the temperature distribution were obtained. The electrode erosion experiment of brass, stainless steel, coppertungsten and graphite was carried out under 100kA microsecond arc for 300 pulses and 36 C charge transfer. The experimental results show that the mass loss rate of the four electrodes materials is 6.39mg/C for brass, 6-38mg/C for stainless steel, 4.19 mg/C for coppertungsten and 1.19mg/C for graphite respectively．
Surface layer temperature distribution of electrode was analyzed based on the equation of heat conduction. The parameters of arc and electrode material that influence the temperature distribution were obtained. The electrode erosion experiment of brass, stainless steel, coppertungsten and graphite was carried out under 100kA microsecond arc for 300 pulses and 36 C charge transfer. The experimental results show that the mass loss rate of the four electrodes materials is 6.39mg/C for brass, 6-38mg/C for stainless steel, 4.19 mg/C for coppertungsten and 1.19mg/C for graphite respectively．
2004,
16.
Abstract:
A four pulsed voltage system (FPVS) has been built based on a 2MeV linear induction accelerator (LIA) injector. With the FPVS, some research on the multipulsed vacuum diode was taken. The pulse duration is 100ns and pulse to pulse duration is less than 500ns. The pulsed diode voltages are around 500kV. In this paper, the work on multipulse emitting characteristics of velvet cathode is introduced. The CCD photos of emitting cathode indicate that the velvet can't emit electrons uniformly under multi-pulse condition. At the same time, the effects of beam load and cathode plasma to multi-pulse emitting and beam to beam electron energy dispersion are also discussed. The experimental results indicate that the cathode plasma can reduce the effective distance between cathode and anode of diode
A four pulsed voltage system (FPVS) has been built based on a 2MeV linear induction accelerator (LIA) injector. With the FPVS, some research on the multipulsed vacuum diode was taken. The pulse duration is 100ns and pulse to pulse duration is less than 500ns. The pulsed diode voltages are around 500kV. In this paper, the work on multipulse emitting characteristics of velvet cathode is introduced. The CCD photos of emitting cathode indicate that the velvet can't emit electrons uniformly under multi-pulse condition. At the same time, the effects of beam load and cathode plasma to multi-pulse emitting and beam to beam electron energy dispersion are also discussed. The experimental results indicate that the cathode plasma can reduce the effective distance between cathode and anode of diode
2004,
16.
Abstract:
The paper has derived the formulas from Ampere's Law and Gauss law, which are used to evaluate the electrical parameters of commonvertexcoaxialcircularconeslike and disklike ideal transmission lines, such as capacitance, inductance and impedance. However, some of these formulas are analytical expressions while the others are only some method to get numeric solution. The expressions or method has been validated by a practical example and sequentially used to evaluate a new design.
The paper has derived the formulas from Ampere's Law and Gauss law, which are used to evaluate the electrical parameters of commonvertexcoaxialcircularconeslike and disklike ideal transmission lines, such as capacitance, inductance and impedance. However, some of these formulas are analytical expressions while the others are only some method to get numeric solution. The expressions or method has been validated by a practical example and sequentially used to evaluate a new design.
2004,
16.
Abstract:
The characteristics of a hydrogen thyratron driven by power MOSFETs to produce high voltage, fast pulses is investigated. The basic structure of the thyratorn is introduced. The effects of the reservoir heater voltage, cathode heater voltage and characteristics of grid drive pulses on the output performance are carefully examined and shown in figures. With this pulse generator, pulses with amplitude up to 15kV into 75Ω, risetime less than 10ns, and jitter less than 1ns can be achieved．
The characteristics of a hydrogen thyratron driven by power MOSFETs to produce high voltage, fast pulses is investigated. The basic structure of the thyratorn is introduced. The effects of the reservoir heater voltage, cathode heater voltage and characteristics of grid drive pulses on the output performance are carefully examined and shown in figures. With this pulse generator, pulses with amplitude up to 15kV into 75Ω, risetime less than 10ns, and jitter less than 1ns can be achieved．
2004,
16.
Abstract:
A method for optimization design of the main switch (using in 12MeV linear induction accelerator) was introduced. The switch's inductance was decreased from 63.7nH to 35nH by optimizing the configuration of the main switch and the size of the electric poles so that the accelerating cavity can get a better rising time of 27ns. The accelerator's performance can be effectively improved through this method, the feasibility of the method is also proved by testing．
A method for optimization design of the main switch (using in 12MeV linear induction accelerator) was introduced. The switch's inductance was decreased from 63.7nH to 35nH by optimizing the configuration of the main switch and the size of the electric poles so that the accelerating cavity can get a better rising time of 27ns. The accelerator's performance can be effectively improved through this method, the feasibility of the method is also proved by testing．
2004,
16.
Abstract:
Electron optics property of a high power electron accelerator (450kW) using the SLAC226 program was studied in this paper. Some results such as the potential distribution in the gun, the trace space plot of ray in anode plane, the impact on beam focusing caused by the spacing of diode were obtained. Through calculating, the best distance between anode and cathode is about 58.5mm. And some analysis of space-charge effects were also presented．
Electron optics property of a high power electron accelerator (450kW) using the SLAC226 program was studied in this paper. Some results such as the potential distribution in the gun, the trace space plot of ray in anode plane, the impact on beam focusing caused by the spacing of diode were obtained. Through calculating, the best distance between anode and cathode is about 58.5mm. And some analysis of space-charge effects were also presented．
2004,
16.
Abstract:
Circuit inductance exists at discharging circuit of transmissionline, it includes the inductance at the main switch of thyratron when conducts, the linking inductance between the linking cables, the matching resistance inductance and the load inductance. When a long pulse is generated by transmissionline, the circuit inductance can be omitted. However, when the pulse is short (such as shorter than 200 ns), especially when ferromagnetic core kicker acts as the load, the effect is obvious. The short pulse current is needed in order to generate long time interval synchronous radiation light pulses by using online assembly of pulse convex orbit and DC convex orbit. This paper analyses the effect and presents several experimental results. It also supposes two practical cases to decrease the
Circuit inductance exists at discharging circuit of transmissionline, it includes the inductance at the main switch of thyratron when conducts, the linking inductance between the linking cables, the matching resistance inductance and the load inductance. When a long pulse is generated by transmissionline, the circuit inductance can be omitted. However, when the pulse is short (such as shorter than 200 ns), especially when ferromagnetic core kicker acts as the load, the effect is obvious. The short pulse current is needed in order to generate long time interval synchronous radiation light pulses by using online assembly of pulse convex orbit and DC convex orbit. This paper analyses the effect and presents several experimental results. It also supposes two practical cases to decrease the
2004,
16.
Abstract:
The scalar method and vector method were applied in the analysis of color seperation grating of oblique incident wave. This paper checks the effect of color seperation grating when the angle of incident wave changes and tries to give the region of incident angle when the color seperation grating has good effect. The results verify that the color seperation grating can be efficient and can satisfy the ICF system when the angle of indident wave is less than 5°.
The scalar method and vector method were applied in the analysis of color seperation grating of oblique incident wave. This paper checks the effect of color seperation grating when the angle of incident wave changes and tries to give the region of incident angle when the color seperation grating has good effect. The results verify that the color seperation grating can be efficient and can satisfy the ICF system when the angle of indident wave is less than 5°.
2004,
16.
Abstract:
There are torsion components of multi rotation degree of freedom in the optics mechanism system disturbed by specifically environment of vibration. The disturbances induce deflection jitter of directional angle of the beam emitted by the system, result in the centralization degree of radiant energy falling in dynamic spread form. With adopting means of probability and statistics, the representative testing result of the beam random jittering is analyzed by dualistic statistics. On the basis that factual amplitude distribution of jitter is close to characteristic of the normal law, it is discussed from cumulative radiant effects the distribution characteristic of energy deposition on the radiated surface by directional beam and the approximate evaluation means about energy diffusion extent
There are torsion components of multi rotation degree of freedom in the optics mechanism system disturbed by specifically environment of vibration. The disturbances induce deflection jitter of directional angle of the beam emitted by the system, result in the centralization degree of radiant energy falling in dynamic spread form. With adopting means of probability and statistics, the representative testing result of the beam random jittering is analyzed by dualistic statistics. On the basis that factual amplitude distribution of jitter is close to characteristic of the normal law, it is discussed from cumulative radiant effects the distribution characteristic of energy deposition on the radiated surface by directional beam and the approximate evaluation means about energy diffusion extent
2004,
16.
Abstract:
The evaluation of microarray optical components is a new task in the field of optical test. The improved Foucault knifeedge test technology has many advantages as real time, digital, precision, etc. This paper introduces the principle and the experimental setup of knifeedge digital test of the surface characterization of micromirror array, and describes the key steps in processing the images of the micromirrors recorded by the CCD detector as: (1)precisely determine the knifeedge position correspond to the darkness threshold of every pixel; (2)determine the slope error of the surface area correspond to the given pixels; (3)reconstruct the examined surface. Furthermore, it also presents some elementary experimental results that the surface error is up to nm level.
The evaluation of microarray optical components is a new task in the field of optical test. The improved Foucault knifeedge test technology has many advantages as real time, digital, precision, etc. This paper introduces the principle and the experimental setup of knifeedge digital test of the surface characterization of micromirror array, and describes the key steps in processing the images of the micromirrors recorded by the CCD detector as: (1)precisely determine the knifeedge position correspond to the darkness threshold of every pixel; (2)determine the slope error of the surface area correspond to the given pixels; (3)reconstruct the examined surface. Furthermore, it also presents some elementary experimental results that the surface error is up to nm level.
2004,
16.
Abstract:
Experimental results of green noise suppression in a diode-pumped intracavity-doubled Nd:YAG laser by inserting a QWP between the Nd:YAG rod and mirror, or between the KTP frequency doubler and mirror,and using two cross-doubled crystals are presented. It is shown that the green noise in a folded resonator can be effectively reduced if one of the above methods is used. The introduction of two cross-doubled crystals has reduced the noise by 18％~25%.The experimental results are consistent with theoretical predications.Some problems in the experiment and further improvements are discussed．
Experimental results of green noise suppression in a diode-pumped intracavity-doubled Nd:YAG laser by inserting a QWP between the Nd:YAG rod and mirror, or between the KTP frequency doubler and mirror,and using two cross-doubled crystals are presented. It is shown that the green noise in a folded resonator can be effectively reduced if one of the above methods is used. The introduction of two cross-doubled crystals has reduced the noise by 18％~25%.The experimental results are consistent with theoretical predications.Some problems in the experiment and further improvements are discussed．
2004,
16.
Abstract:
The characteristics and limits of the general three models of radiative transfer in the atmosphere are discussed. Numerical tests were carried out by means of both the radiative transfer's law and the transmittances measurements in the real atmosphere. The results show that there are very good agreements between the transmittance measured in the fields and calculated by the model for COIL and HF overtone 20P4 lines, but big error for HF overtone 20P5. Moreover, the significant influence of aerosol types on transmittance of the laser beam through the atmosphere is studied.
The characteristics and limits of the general three models of radiative transfer in the atmosphere are discussed. Numerical tests were carried out by means of both the radiative transfer's law and the transmittances measurements in the real atmosphere. The results show that there are very good agreements between the transmittance measured in the fields and calculated by the model for COIL and HF overtone 20P4 lines, but big error for HF overtone 20P5. Moreover, the significant influence of aerosol types on transmittance of the laser beam through the atmosphere is studied.
2004,
16.
Abstract:
A 1Hz repetitionrate electron beam generator is being developed to pump HF/DF chemical laser. The pulse width, peak current and peak voltage of the electron beams are 100ns, 100kA and 450kV, respectively. It uses two diodes, two waterfilled pulse forming lines, three lasertriggered switches, a pulse transformer and one set of energy storage capacitors. The primary, secondary and mutual inductances of the pulse transformer are 331nH, 26.5mH and 1.9μＨ, respectively. The capacitance of each pulse forming line is 8.15nF. Its inductance and impedance are 300nH and 6.2Ω, respectively. The breaking factor is 03 at 1MV charging voltage. The output energy of a nonchain HF/DF chemical laser pulse is expected to be 250J at 38μm.
A 1Hz repetitionrate electron beam generator is being developed to pump HF/DF chemical laser. The pulse width, peak current and peak voltage of the electron beams are 100ns, 100kA and 450kV, respectively. It uses two diodes, two waterfilled pulse forming lines, three lasertriggered switches, a pulse transformer and one set of energy storage capacitors. The primary, secondary and mutual inductances of the pulse transformer are 331nH, 26.5mH and 1.9μＨ, respectively. The capacitance of each pulse forming line is 8.15nF. Its inductance and impedance are 300nH and 6.2Ω, respectively. The breaking factor is 03 at 1MV charging voltage. The output energy of a nonchain HF/DF chemical laser pulse is expected to be 250J at 38μm.
2004,
16.
Abstract:
The pulse inline holography has been applized to construct the holography system and the high accuracy synchronization system.The hologram of microjet produced by explosive was gotten in the experiment. When the hologram was reconsructed, the distribution and the size of particle were analyzed. The statistical result of particles shows that the maximum size is 300μm and the minimum size is 30μm. This measurcment system was proved that the pulsed in line holography can measure the high velocity microjet.
The pulse inline holography has been applized to construct the holography system and the high accuracy synchronization system.The hologram of microjet produced by explosive was gotten in the experiment. When the hologram was reconsructed, the distribution and the size of particle were analyzed. The statistical result of particles shows that the maximum size is 300μm and the minimum size is 30μm. This measurcment system was proved that the pulsed in line holography can measure the high velocity microjet.
2004,
16.
Abstract:
The transient temperature distribution in the Nd:YAG laser rod repeatedly pulsepumped by high power ring-LD array was simulated in detail by using ray tracing method and finite element method. The transient temperature distributions at different pump periods, pump frequencies and pump widths were analyzed and compared. The result indicated that when high power ring-LD array pumped repeatedly, the core temperature of the rod had sawtooth distribution，and the temperature of the rod rose as the pump frequency or pump width rose. At last the temperature had periodical distribution with time．
The transient temperature distribution in the Nd:YAG laser rod repeatedly pulsepumped by high power ring-LD array was simulated in detail by using ray tracing method and finite element method. The transient temperature distributions at different pump periods, pump frequencies and pump widths were analyzed and compared. The result indicated that when high power ring-LD array pumped repeatedly, the core temperature of the rod had sawtooth distribution，and the temperature of the rod rose as the pump frequency or pump width rose. At last the temperature had periodical distribution with time．
2004,
16.
Abstract:
A pulsed magnetic field simulation system was developed to study the effect of microelectronic system under strong magnetic pulses. In the experiment, personal computers were put into the electromagnetic environment of the simulator. Coupling paths, interference threshold, the relation of the threshold with rising time and duration time of the field were studied by changing the peak value, duration time and rising time of the simulated pulsed magnetic field. Results show that the connecting cables are the main paths that introduce interference, simple shielding can reduce the interference at some extent, and the interference is more potential to affect the microelectronic system if its time derivative is larger．
A pulsed magnetic field simulation system was developed to study the effect of microelectronic system under strong magnetic pulses. In the experiment, personal computers were put into the electromagnetic environment of the simulator. Coupling paths, interference threshold, the relation of the threshold with rising time and duration time of the field were studied by changing the peak value, duration time and rising time of the simulated pulsed magnetic field. Results show that the connecting cables are the main paths that introduce interference, simple shielding can reduce the interference at some extent, and the interference is more potential to affect the microelectronic system if its time derivative is larger．
2004,
16.
Abstract:
A set of selfconsistent nonlinear equations in the electron guiding center coordinate is derived for the study of the behavior of the coaxial Gyrotravellingwavetube(GyroTWT) amplifier. Calculations show that: the input signal grows faster and gets saturated earlier at a slightly lower radiation power with the increasing of the ratio of the inner to outer radius; power loss on the walls of the inner and outer conductor decrease with the increasing of the ratio. Using an electron beam of 90kV, 10A and velocity ratio of 1.0 with 3% axial velocity spread, 230kW peak output power is obtained by calculation at the frequency range of 34.26 to 36.78GHz, the gain, efficiency and bandwidth are 46.6dB, 25.5% and 7.0%, respectively. The maximum loss on the walls of the coaxial waveguide are
A set of selfconsistent nonlinear equations in the electron guiding center coordinate is derived for the study of the behavior of the coaxial Gyrotravellingwavetube(GyroTWT) amplifier. Calculations show that: the input signal grows faster and gets saturated earlier at a slightly lower radiation power with the increasing of the ratio of the inner to outer radius; power loss on the walls of the inner and outer conductor decrease with the increasing of the ratio. Using an electron beam of 90kV, 10A and velocity ratio of 1.0 with 3% axial velocity spread, 230kW peak output power is obtained by calculation at the frequency range of 34.26 to 36.78GHz, the gain, efficiency and bandwidth are 46.6dB, 25.5% and 7.0%, respectively. The maximum loss on the walls of the coaxial waveguide are
2004,
16.
Abstract:
A simple model was developed to investigate the generation mechanism of virtual cathode oscillation microwave based on space-charge effect under small signal condition. With this model, the generated microwave frequency in a vircator an be calculated. On the basis of theoretical analysis, an improved virtual cathode oscillator was brought forward. In this configure, a resonant cavity is located behind anode, the cavity is very small so that virtual cathode couldn't be formed in it, the reflected beem current may excited a cavity mode, which modulates injected beam; and microwave is extracted in coaxial structure.2.5D PIC numerical simulation was conducted to study it. Microwave pulse power of 1GW at 3.66GHz for 520kV and 12.5kA injecting e-beam was obtained, power efficiency was about 15.3
A simple model was developed to investigate the generation mechanism of virtual cathode oscillation microwave based on space-charge effect under small signal condition. With this model, the generated microwave frequency in a vircator an be calculated. On the basis of theoretical analysis, an improved virtual cathode oscillator was brought forward. In this configure, a resonant cavity is located behind anode, the cavity is very small so that virtual cathode couldn't be formed in it, the reflected beem current may excited a cavity mode, which modulates injected beam; and microwave is extracted in coaxial structure.2.5D PIC numerical simulation was conducted to study it. Microwave pulse power of 1GW at 3.66GHz for 520kV and 12.5kA injecting e-beam was obtained, power efficiency was about 15.3
2004,
16.
Abstract:
In order to settle the difficulty of the EMP experiment on onedimension metal structure，the conception of one-dimension EMP simulator was given，and in this paper，the induced current by EMP on one-dimension metal structure was calculated with numerical ways. The results and analysis illustrated the feasibility of setting up one-dimension EMP simulator. Finally，several problems，which may emerge in design，were discussed theoretically.
In order to settle the difficulty of the EMP experiment on onedimension metal structure，the conception of one-dimension EMP simulator was given，and in this paper，the induced current by EMP on one-dimension metal structure was calculated with numerical ways. The results and analysis illustrated the feasibility of setting up one-dimension EMP simulator. Finally，several problems，which may emerge in design，were discussed theoretically.
2004,
16.
Abstract:
Because of the reflection on the surface of the gratings, the diffractive efficiency of the components can't meet the requirement of the ICF system. To resolve the problem this paper introduces a kind of scheme adopted coating to reduce the reflection of the gratings' surface. The coating anti-reflection technology of the CSG is discussed in detail. Using the scalar theory the design parameters have been decided and the structure parameters of the gratings have been optimized. The optimized value of the trough depth of the CSG is 2.84μm, and the optimized value of the film depth is 71.2nm. The numerical results show that the reflection of the gratings' surface has been eliminated drastically. The validity of the anti-reflection technology is distinctly in the application of the high pow
Because of the reflection on the surface of the gratings, the diffractive efficiency of the components can't meet the requirement of the ICF system. To resolve the problem this paper introduces a kind of scheme adopted coating to reduce the reflection of the gratings' surface. The coating anti-reflection technology of the CSG is discussed in detail. Using the scalar theory the design parameters have been decided and the structure parameters of the gratings have been optimized. The optimized value of the trough depth of the CSG is 2.84μm, and the optimized value of the film depth is 71.2nm. The numerical results show that the reflection of the gratings' surface has been eliminated drastically. The validity of the anti-reflection technology is distinctly in the application of the high pow
2004,
16.
Abstract:
By the general freezing-dry technology, low density, open-celled microporous polymeric foams, such as polystyrene, can be fabricated. The density of polystyrene foam is 0.02~0.1g/cm3, and the average cell size is 1~20μm. The factors that affect the cellular structure of foams, such as the process of phase separation between polymer and solvent, the system of polymer and solvent, and the freezing rate have been studied. In order to obtain the homogeneous defect-free foams, the technology must pick a system in which the theta temperature of solvent to polymer is higher than the solvent melting point temperature, and use unidirectional freezing whose quench rate exceeds 100℃/min．
By the general freezing-dry technology, low density, open-celled microporous polymeric foams, such as polystyrene, can be fabricated. The density of polystyrene foam is 0.02~0.1g/cm3, and the average cell size is 1~20μm. The factors that affect the cellular structure of foams, such as the process of phase separation between polymer and solvent, the system of polymer and solvent, and the freezing rate have been studied. In order to obtain the homogeneous defect-free foams, the technology must pick a system in which the theta temperature of solvent to polymer is higher than the solvent melting point temperature, and use unidirectional freezing whose quench rate exceeds 100℃/min．
2004,
16.
Abstract:
19.6nm Nelike Ge Xray laser (XRL) can be used as a source to diagnose RayleighTaylor instability in laser induced plasma. In this paper, systemic optimum designs and theoretical analysis to Nelike Ge XRL driven by premain short pulses were conducted by a series of codes, which had been tested by experiments. Simulation results show that, adopting driven conditions of 2%~3% prepulse , 6~8ns premain pulse interval and 40TW/cm2 power intensity，a gain area of 19.6nm laser line beyond 60μm and gain duration of 90ps can be obtained. Furthermore, with 16mm plane target, the gain gets to 11.8/cm, and if 6mrad/cm curved target is adopted, it reaches to 13.3/cm, and small signal gainlength product gainlength product of single target is about 21.3, which means that saturated gain
19.6nm Nelike Ge Xray laser (XRL) can be used as a source to diagnose RayleighTaylor instability in laser induced plasma. In this paper, systemic optimum designs and theoretical analysis to Nelike Ge XRL driven by premain short pulses were conducted by a series of codes, which had been tested by experiments. Simulation results show that, adopting driven conditions of 2%~3% prepulse , 6~8ns premain pulse interval and 40TW/cm2 power intensity，a gain area of 19.6nm laser line beyond 60μm and gain duration of 90ps can be obtained. Furthermore, with 16mm plane target, the gain gets to 11.8/cm, and if 6mrad/cm curved target is adopted, it reaches to 13.3/cm, and small signal gainlength product gainlength product of single target is about 21.3, which means that saturated gain
2004,
16.
Abstract:
A commercial CCD camera is used to image UV laser beams and soft X rays instead of expensive UV CCD and inconvenient X-ray film or X-ray CCD after removing automatic gain correction, protection window and setting-up correction coefficient to be 1. The experimental results show that a revised commercial CCD camera can be used to cheaply diagnose collimation,focusing, etc in laser and plasma interaction research．
A commercial CCD camera is used to image UV laser beams and soft X rays instead of expensive UV CCD and inconvenient X-ray film or X-ray CCD after removing automatic gain correction, protection window and setting-up correction coefficient to be 1. The experimental results show that a revised commercial CCD camera can be used to cheaply diagnose collimation,focusing, etc in laser and plasma interaction research．
2004,
16.
Abstract:
This article briefly describes the principle of Thomson scattering to measure the electron temperature, and gives the way of calculating electron temperature, which adapted to the Nd:glass laser scattering apparatus. Then based on the principle of probability it analyzes the effect range of electron temperature that was measured by infrared laser scattering apparatus on HT7 superconducting tokamak, and the effective range of electron temperature is １００eV～5keV．
This article briefly describes the principle of Thomson scattering to measure the electron temperature, and gives the way of calculating electron temperature, which adapted to the Nd:glass laser scattering apparatus. Then based on the principle of probability it analyzes the effect range of electron temperature that was measured by infrared laser scattering apparatus on HT7 superconducting tokamak, and the effective range of electron temperature is １００eV～5keV．
2004,
16.
Abstract:
With PETA as the monomer, benzoin ethyl ether as the initiator and the energy of UV light, poly(acrylate) gelation is produced in different solvents and foams are prepared via vacuum drying technique. The polymer solvent parameter is 19.0 decided with the methods of the theoretical calculation and experiments. Solvent with phenyl and alicyclic group in molecule makes the initiator impassive, whereas solvent with ketone, alky halide, lipoid, ether and acylamide group in molecule makes the initiator active.
With PETA as the monomer, benzoin ethyl ether as the initiator and the energy of UV light, poly(acrylate) gelation is produced in different solvents and foams are prepared via vacuum drying technique. The polymer solvent parameter is 19.0 decided with the methods of the theoretical calculation and experiments. Solvent with phenyl and alicyclic group in molecule makes the initiator impassive, whereas solvent with ketone, alky halide, lipoid, ether and acylamide group in molecule makes the initiator active.
2004,
16.
Abstract:
The process of nonequilibrium radiation ablation of CH foil has been numerically studied using 1D RDMG code of multigroupnonequilibrium radiation hydrodynamic under the condition of radiation source of ShenguangII hohlraum，meanwhile different ablation images from the process of nonequilibrium radiative ablation and the relative scaling laws are obtained. Numerical results show that both electron temperatue and ion temperature separate from radiation temperature and the spectra of radiation flux is nonequilibrium inside CH during the whole process of CH foil ablation. The ablative depth is shorter and shock wave is weaker compared with equilibrium ablation because nonequilibrium radiation ablation contains ionization wave, radiation heating wave and radiation ablation wave.
The process of nonequilibrium radiation ablation of CH foil has been numerically studied using 1D RDMG code of multigroupnonequilibrium radiation hydrodynamic under the condition of radiation source of ShenguangII hohlraum，meanwhile different ablation images from the process of nonequilibrium radiative ablation and the relative scaling laws are obtained. Numerical results show that both electron temperatue and ion temperature separate from radiation temperature and the spectra of radiation flux is nonequilibrium inside CH during the whole process of CH foil ablation. The ablative depth is shorter and shock wave is weaker compared with equilibrium ablation because nonequilibrium radiation ablation contains ionization wave, radiation heating wave and radiation ablation wave.
