S. Babu, Asheel Kumar, Ram Jeet, Arvind Kumar, Dr. Ashish Varma
Stimulated Raman forward scattering (SRFS) of an intense X-mode laser pump in a preformed parabolic plasma density profile is investigated. The laser pump excites a plasma wave and one/two electromagnetic sideband waves. In Raman forward scattering, the growth rate of the parametric instability scales as two-third powers of the pump amplitude and increases linearly with cyclotron frequency.
{"title":"Stimulated Raman Scattering of X-Mode Laser in a Plasma Channel","authors":"S. Babu, Asheel Kumar, Ram Jeet, Arvind Kumar, Dr. Ashish Varma","doi":"10.1155/2021/9919467","DOIUrl":"https://doi.org/10.1155/2021/9919467","url":null,"abstract":"Stimulated Raman forward scattering (SRFS) of an intense X-mode laser pump in a preformed parabolic plasma density profile is investigated. The laser pump excites a plasma wave and one/two electromagnetic sideband waves. In Raman forward scattering, the growth rate of the parametric instability scales as two-third powers of the pump amplitude and increases linearly with cyclotron frequency.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"37 1","pages":"1-10"},"PeriodicalIF":0.9,"publicationDate":"2021-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72555395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For low carbon energy generation, a very large exchange of electricity generators is existentially vital within the next number of years by power stations preferably at considerably low cost than the present installations. When considering the million times higher nuclear energy per reaction than chemical, the usual hydrogen fusion with abundant boron fuel is used for environmentally clean electricity generators. Instead of usually needed ignition temperatures of hundreds of million degrees Celsius, it is possible to use nonthermal ignition pressures from now available CPA laser pulses. In this non-LTE scheme, there is no need for high compression, the medium of hydrogen-boron-11 temperatures is low, and therefore the bremsstrahlung losses practically do not exist. The neutron, created by secondary reactions, elimination device includes tin and is arranged such that the neutrons are brought to nuclear reactions with the tin. We suggest adding the tin that has proven to be particularly advantageous because of its high effective cross section, and the neutron reactions with tin transform the tin nuclei into stable nuclei with a higher atomic weight.
{"title":"Elimination of Secondary Neutrons from Laser Proton-Boron Fusion","authors":"H. Hora, S. Eliezer, N. Nissim","doi":"10.1155/2021/9978899","DOIUrl":"https://doi.org/10.1155/2021/9978899","url":null,"abstract":"For low carbon energy generation, a very large exchange of electricity generators is existentially vital within the next number of years by power stations preferably at considerably low cost than the present installations. When considering the million times higher nuclear energy per reaction than chemical, the usual hydrogen fusion with abundant boron fuel is used for environmentally clean electricity generators. Instead of usually needed ignition temperatures of hundreds of million degrees Celsius, it is possible to use nonthermal ignition pressures from now available CPA laser pulses. In this non-LTE scheme, there is no need for high compression, the medium of hydrogen-boron-11 temperatures is low, and therefore the bremsstrahlung losses practically do not exist. The neutron, created by secondary reactions, elimination device includes tin and is arranged such that the neutrons are brought to nuclear reactions with the tin. We suggest adding the tin that has proven to be particularly advantageous because of its high effective cross section, and the neutron reactions with tin transform the tin nuclei into stable nuclei with a higher atomic weight.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"77 1","pages":"1-3"},"PeriodicalIF":0.9,"publicationDate":"2021-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82379510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<jats:p>The perturbation electron density and stopping power caused by the movement of charged particles above two-dimensional quantum electron gases (2DQEG) have been studied in numerous works using the quantum hydrodynamic (QHD) theory. In this paper, the QHD is modified by introducing the two-dimensional electron exchange-correlation potential at high density <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>x</mi> <mi>c</mi> <mn>2</mn> <mtext>DH</mtext> </mrow> </msub> </math> </jats:inline-formula> and the pump wave modulations. Based on the modified QHD, the perturbation electron density and stopping power are calculated for pump waves with various parameters. The results show that the stopping power values are more accurate after considering <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2"> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>x</mi> <mi>c</mi> <mn>2</mn> <mtext>DH</mtext> </mrow> </msub> </math> </jats:inline-formula>. Under the modulation of pump waves with the wavelength from <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3"> <mn>0.1</mn> <mtext>nm</mtext> </math> </jats:inline-formula> to <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M4"> <mn>0.1</mn> <mtext>cm</mtext> </math> </jats:inline-formula>, the perturbation electron density of 2DQEG and the stopping power of charged particles show periodic changes. Under the modulation of pump waves with <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M5"> <mi>λ</mi> <mo>=</mo> <mn>1.76</mn> <mo>×</mo> <msup> <mrow> <mn>10</mn> </mrow> <mrow> <mo>−</mo> <mn>4</mn>
{"title":"Stopping Power Modulation by Pump Waves of Charged Particles Moving above Two-Dimensional Electron Gases","authors":"Yahong Yang, Ya Zhang, L. Yi, Wei Jiang","doi":"10.1155/2021/5580444","DOIUrl":"https://doi.org/10.1155/2021/5580444","url":null,"abstract":"<jats:p>The perturbation electron density and stopping power caused by the movement of charged particles above two-dimensional quantum electron gases (2DQEG) have been studied in numerous works using the quantum hydrodynamic (QHD) theory. In this paper, the QHD is modified by introducing the two-dimensional electron exchange-correlation potential at high density <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\">\u0000 <msub>\u0000 <mrow>\u0000 <mi>V</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mi>x</mi>\u0000 <mi>c</mi>\u0000 <mn>2</mn>\u0000 <mtext>DH</mtext>\u0000 </mrow>\u0000 </msub>\u0000 </math>\u0000 </jats:inline-formula> and the pump wave modulations. Based on the modified QHD, the perturbation electron density and stopping power are calculated for pump waves with various parameters. The results show that the stopping power values are more accurate after considering <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\">\u0000 <msub>\u0000 <mrow>\u0000 <mi>V</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mi>x</mi>\u0000 <mi>c</mi>\u0000 <mn>2</mn>\u0000 <mtext>DH</mtext>\u0000 </mrow>\u0000 </msub>\u0000 </math>\u0000 </jats:inline-formula>. Under the modulation of pump waves with the wavelength from <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M3\">\u0000 <mn>0.1</mn>\u0000 <mtext>nm</mtext>\u0000 </math>\u0000 </jats:inline-formula> to <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M4\">\u0000 <mn>0.1</mn>\u0000 <mtext>cm</mtext>\u0000 </math>\u0000 </jats:inline-formula>, the perturbation electron density of 2DQEG and the stopping power of charged particles show periodic changes. Under the modulation of pump waves with <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M5\">\u0000 <mi>λ</mi>\u0000 <mo>=</mo>\u0000 <mn>1.76</mn>\u0000 <mo>×</mo>\u0000 <msup>\u0000 <mrow>\u0000 <mn>10</mn>\u0000 </mrow>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>4</mn>\u0000","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"10 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73197918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<jats:p>A detailed study of direct laser-driven electron acceleration in paraxial Laguerre–Gaussian modes corresponding to helical beams <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"> <msub> <mrow> <mtext>LG</mtext> </mrow> <mrow> <mn>0</mn> <mi>m</mi> </mrow> </msub> </math> </jats:inline-formula> with azimuthal modes <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2"> <mi>m</mi> <mo>=</mo> <mfenced open="{" close="}" separators="|"> <mrow> <mn>1,2,3,4,5</mn> </mrow> </mfenced> </math> </jats:inline-formula> is presented. Due to the difference between the ponderomotive force of the fundamental Gaussian beam <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3"> <msub> <mrow> <mtext>LG</mtext> </mrow> <mrow> <mn>00</mn> </mrow> </msub> </math> </jats:inline-formula> and helical beams <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M4"> <msub> <mrow> <mtext>LG</mtext> </mrow> <mrow> <mn>0</mn> <mi>m</mi> </mrow> </msub> </math> </jats:inline-formula>, we found that the optimal beam waist leading to the most energetic electrons at full width at half maximum is more than twice smaller for the latter and corresponds to a few wavelengths <jats:inline-formula> <math xmlns="http://www.w3.org/1998/Math/MathML" id="M5"> <mi mathvariant="normal">Δ</mi> <msub> <mrow> <mi>w</mi> </mrow> <mrow> <mn>0</mn> </mrow> </msub> <mo>=</mo> <mfenced open="{" close="}" separators="|"> <mrow> <
直接激光驱动电子加速的近轴拉盖尔-高斯模式的详细研究，对应于具有方位模式的螺旋光束lg0 mM = 1,2,3,4,5。由于基态高斯光束的质动势与螺旋光束的质动势不同0米;我们发现，在半最大值处，导致全宽处能量最大的电子的最佳束腰比后者小两倍以上，并且对应于几个波长Δ w 0 =P的激光功率为6,11,19 λ 00 = 0.1,1,10 pw。我们还发现，当方位模态m≥3时，最佳腰围应小于Δ w 0 19 λ0 .利用这些最优值，我们观察到电子在螺旋光束中的平均动能增益比基本高斯光束大一个数量级。这种平均能量增益随着方位角指数m的增加而增加，导致在激光传播方向上有几个100 MeV能量的准直电子。
{"title":"Direct Laser-Driven Electron Acceleration and Energy Gain in Helical Beams","authors":"E. Moln'ar, D. Stutman","doi":"10.1155/2021/6645668","DOIUrl":"https://doi.org/10.1155/2021/6645668","url":null,"abstract":"<jats:p>A detailed study of direct laser-driven electron acceleration in paraxial Laguerre–Gaussian modes corresponding to helical beams <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\">\u0000 <msub>\u0000 <mrow>\u0000 <mtext>LG</mtext>\u0000 </mrow>\u0000 <mrow>\u0000 <mn>0</mn>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 </msub>\u0000 </math>\u0000 </jats:inline-formula> with azimuthal modes <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\">\u0000 <mi>m</mi>\u0000 <mo>=</mo>\u0000 <mfenced open=\"{\" close=\"}\" separators=\"|\">\u0000 <mrow>\u0000 <mn>1,2,3,4,5</mn>\u0000 </mrow>\u0000 </mfenced>\u0000 </math>\u0000 </jats:inline-formula> is presented. Due to the difference between the ponderomotive force of the fundamental Gaussian beam <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M3\">\u0000 <msub>\u0000 <mrow>\u0000 <mtext>LG</mtext>\u0000 </mrow>\u0000 <mrow>\u0000 <mn>00</mn>\u0000 </mrow>\u0000 </msub>\u0000 </math>\u0000 </jats:inline-formula> and helical beams <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M4\">\u0000 <msub>\u0000 <mrow>\u0000 <mtext>LG</mtext>\u0000 </mrow>\u0000 <mrow>\u0000 <mn>0</mn>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 </msub>\u0000 </math>\u0000 </jats:inline-formula>, we found that the optimal beam waist leading to the most energetic electrons at full width at half maximum is more than twice smaller for the latter and corresponds to a few wavelengths <jats:inline-formula>\u0000 <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M5\">\u0000 <mi mathvariant=\"normal\">Δ</mi>\u0000 <msub>\u0000 <mrow>\u0000 <mi>w</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mn>0</mn>\u0000 </mrow>\u0000 </msub>\u0000 <mo>=</mo>\u0000 <mfenced open=\"{\" close=\"}\" separators=\"|\">\u0000 <mrow>\u0000 <","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"2 1","pages":"1-13"},"PeriodicalIF":0.9,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73036886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Lei, R. Cheng, Yong-tao Zhao, Xianming Zhou, Yu Wang, Yan Chen, Zhao Wang, Zexian Zhou, Jie Yang, Xinwen Ma
Energy loss of protons with 90 and 100 keV energies penetrating through a hydrogen plasma target has been measured, where the electron density of the plasma is about 1016 cm−3 and the electron temperature is about 1-2 eV. It is found that the energy loss of protons in the plasma is obviously larger than that in cold gas and the experimental results based on the Bethe model calculations can be demonstrated by the variation of effective charge of protons in the hydrogen plasma. The effective charge remains 1 for 100 keV protons, while the value for 90 keV protons decreases to be about 0.92. Moreover, two empirical formulae are employed to extract the effective charge.
{"title":"The Charge State of Protons with 90 and 100 keV Energies Decelerated in Hydrogen Plasma","authors":"Y. Lei, R. Cheng, Yong-tao Zhao, Xianming Zhou, Yu Wang, Yan Chen, Zhao Wang, Zexian Zhou, Jie Yang, Xinwen Ma","doi":"10.1155/2021/6685626","DOIUrl":"https://doi.org/10.1155/2021/6685626","url":null,"abstract":"Energy loss of protons with 90 and 100 keV energies penetrating through a hydrogen plasma target has been measured, where the electron density of the plasma is about 1016 cm−3 and the electron temperature is about 1-2 eV. It is found that the energy loss of protons in the plasma is obviously larger than that in cold gas and the experimental results based on the Bethe model calculations can be demonstrated by the variation of effective charge of protons in the hydrogen plasma. The effective charge remains 1 for 100 keV protons, while the value for 90 keV protons decreases to be about 0.92. Moreover, two empirical formulae are employed to extract the effective charge.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"44 1","pages":"1-7"},"PeriodicalIF":0.9,"publicationDate":"2021-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87131401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chunxia Li, Xiao Jin, Ganping Wang, Beizhen Zhang, H. Gong, Y. Gan, Fei Li, F. Song
Foilless diode are widely used in high-power microwave devices, but the traditional foilless diodes have large volume, heavy weight, and high power consumption, which are not conducive to the application of high-power microwave system on mobile platform. In order to reduce the size of the foilless diode, improve the transmission efficiency of electron beams, and reduce the weight and power consumption of the guiding magnetic field system, an axial foilless diode with a composite guiding magnetic field system is developed in this paper. By adjusting the structure size and magnetic field parameters of solenoid coil, permanent magnet, and soft magnet, the configuration of the composite magnetic field is optimized. The diameter of the anode tube is about 40% smaller than that of the original structure, and the weight and power consumption of the guiding magnetic system are about 40% lower than that of the original system when the same axial magnetic field intensity in the uniform region is generated. When the magnetic field strength of the permanent magnet is set as 1.4 T and that of the solenoid coil is in the range of 0.5 T∼1 T, the electron beam transmission efficiency is 100%, and the diode impedance is adjustable in the range of 100 Ω∼240 Ω. The experimental results verify the correctness of the simulation analysis. The experimental results show that when the magnetic field strength of the solenoid coil is 0.98 T (0.5 T) and that of the permanent magnet is 1.4 T, the transmission efficiency of the high-current annular electron beam with a peak voltage of 636 kV (590 kV) and a peak current of 3.3 kA (2.6 kA) is 100%, and the diode impedance is about 194 Ω (220 Ω).
无箔二极管广泛应用于大功率微波器件中，但传统的无箔二极管体积大、重量重、功耗高，不利于大功率微波系统在移动平台上的应用。为了减小无箔二极管的尺寸，提高电子束的传输效率，降低引导磁场系统的重量和功耗，本文研制了一种具有复合引导磁场系统的轴向无箔二极管。通过调整电磁线圈、永磁体和软磁体的结构尺寸和磁场参数，优化复合磁场的配置。在均匀区产生相同轴向磁场强度时，阳极管直径比原结构小40%左右，导磁系统重量和功耗比原系统低40%左右。当永磁体的磁场强度设置为1.4 T，螺线管线圈的磁场强度设置为0.5 T ~ 1 T时，电子束传输效率为100%，二极管阻抗在100 Ω ~ 240 Ω范围内可调。实验结果验证了仿真分析的正确性。实验结果表明，当电磁线圈的磁场强度为0.98 T (0.5 T)，永磁体的磁场强度为1.4 T时，峰值电压为636 kV (590 kV)，峰值电流为3.3 kA (2.6 kA)的大电流环形电子束的传输效率为100%，二极管阻抗约为194 Ω (220 Ω)。
{"title":"An Axial Foilless Diode Guided by Composite Magnetic Field for the Production of Relativistic Electron Beams","authors":"Chunxia Li, Xiao Jin, Ganping Wang, Beizhen Zhang, H. Gong, Y. Gan, Fei Li, F. Song","doi":"10.1155/2021/6610870","DOIUrl":"https://doi.org/10.1155/2021/6610870","url":null,"abstract":"Foilless diode are widely used in high-power microwave devices, but the traditional foilless diodes have large volume, heavy weight, and high power consumption, which are not conducive to the application of high-power microwave system on mobile platform. In order to reduce the size of the foilless diode, improve the transmission efficiency of electron beams, and reduce the weight and power consumption of the guiding magnetic field system, an axial foilless diode with a composite guiding magnetic field system is developed in this paper. By adjusting the structure size and magnetic field parameters of solenoid coil, permanent magnet, and soft magnet, the configuration of the composite magnetic field is optimized. The diameter of the anode tube is about 40% smaller than that of the original structure, and the weight and power consumption of the guiding magnetic system are about 40% lower than that of the original system when the same axial magnetic field intensity in the uniform region is generated. When the magnetic field strength of the permanent magnet is set as 1.4 T and that of the solenoid coil is in the range of 0.5 T∼1 T, the electron beam transmission efficiency is 100%, and the diode impedance is adjustable in the range of 100 Ω∼240 Ω. The experimental results verify the correctness of the simulation analysis. The experimental results show that when the magnetic field strength of the solenoid coil is 0.98 T (0.5 T) and that of the permanent magnet is 1.4 T, the transmission efficiency of the high-current annular electron beam with a peak voltage of 636 kV (590 kV) and a peak current of 3.3 kA (2.6 kA) is 100%, and the diode impedance is about 194 Ω (220 Ω).","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"320 1","pages":"1-9"},"PeriodicalIF":0.9,"publicationDate":"2021-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78115907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is shown that the dynamics of electrons accelerated in narrow capillary waveguides is significantly influenced by the parametric excitation of their betatron oscillations. On the one hand, this excitation can irreversibly spoil the emittance of an accelerated electron bunch that limits the possibilities of their practical use. On the other hand, controlled parametric excitation of betatron oscillations can be used to generate short-pulse sources of synchrotron radiation. The article analyzes the regions of parametric instabilities, their dependence on the parameters of accelerated electron bunches and guiding structures, and their influence on the dynamics of accelerated electrons. The parameters of the generated synchrotron radiation are also estimated. Measurements of the spectral parameters of synchrotron radiation can serve as a tool for diagnostics of betatron oscillations and their excitation in the case of parametric resonances.
{"title":"On Peculiarities of Betatron Oscillations of Accelerated Electron Bunches in Capillary Waveguides","authors":"M. Veysman","doi":"10.1155/2021/6655499","DOIUrl":"https://doi.org/10.1155/2021/6655499","url":null,"abstract":"It is shown that the dynamics of electrons accelerated in narrow capillary waveguides is significantly influenced by the parametric excitation of their betatron oscillations. On the one hand, this excitation can irreversibly spoil the emittance of an accelerated electron bunch that limits the possibilities of their practical use. On the other hand, controlled parametric excitation of betatron oscillations can be used to generate short-pulse sources of synchrotron radiation. The article analyzes the regions of parametric instabilities, their dependence on the parameters of accelerated electron bunches and guiding structures, and their influence on the dynamics of accelerated electrons. The parameters of the generated synchrotron radiation are also estimated. Measurements of the spectral parameters of synchrotron radiation can serve as a tool for diagnostics of betatron oscillations and their excitation in the case of parametric resonances.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"96 4 Pt 1 1","pages":"1-10"},"PeriodicalIF":0.9,"publicationDate":"2021-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89528751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Terahertz (THz) radiation from a plasma cylinder with embedded radial electric and axial magnetic fields is investigated. The plasma density and the electric and magnetic fields are such that the electron plasma frequency is near the electron cyclotron frequency and in the THz regime. Two-dimensional particle-in-cell simulations show that the plasma electrons oscillate not only in the azimuthal direction but also in the radial direction. Spectral analysis shows that the resulting oscillating current pattern has a clearly defined characteristic frequency near the electron cyclotron frequency, suggesting resonance between the cyclotron and plasma oscillations. The resulting far-field THz radiation in the axial direction is also discussed.
{"title":"Terahertz Radiation from a Plasma Cylinder with External Radial Electric and Axial Magnetic Fields","authors":"L. Cao, Wei Yu, M. Yu, C. Yu","doi":"10.1155/2021/6666760","DOIUrl":"https://doi.org/10.1155/2021/6666760","url":null,"abstract":"Terahertz (THz) radiation from a plasma cylinder with embedded radial electric and axial magnetic fields is investigated. The plasma density and the electric and magnetic fields are such that the electron plasma frequency is near the electron cyclotron frequency and in the THz regime. Two-dimensional particle-in-cell simulations show that the plasma electrons oscillate not only in the azimuthal direction but also in the radial direction. Spectral analysis shows that the resulting oscillating current pattern has a clearly defined characteristic frequency near the electron cyclotron frequency, suggesting resonance between the cyclotron and plasma oscillations. The resulting far-field THz radiation in the axial direction is also discussed.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"49 1","pages":"1-6"},"PeriodicalIF":0.9,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90661541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mingjia Li, Qiang Kang, Jie Tan, Min Luo, Fei Xiang
With the development of high-power microwave technology, the output power of the pulse generator is required more and more higher. In this paper, it is realized by increasing the output power of the module while the output impedance of the module changes little. The module of the generator is based on pulse forming network (PFN) and linear transformer (LT). Four Blumlein PFNs with arc-type configuration and 24 Ω characteristic impedance were connected symmetrically to the primary coil of the LTD and driven by two identical laser triggered spark switches to ensure four Blumlein PFNs synchronizing operation. On this basis, a two-stage high-power pulse generator based on PFN-LT is developed. The following technical parameters of the generator were achieved on a 12 Ω high-power solid resistor: output voltage amplitude of ∼250 kV and output power of ∼5.2 GW at a repetition rate of 5 Hz.
{"title":"A High-Power Pulse Generator Based on Pulse Forming Network and Linear Transformer","authors":"Mingjia Li, Qiang Kang, Jie Tan, Min Luo, Fei Xiang","doi":"10.1155/2021/6686530","DOIUrl":"https://doi.org/10.1155/2021/6686530","url":null,"abstract":"With the development of high-power microwave technology, the output power of the pulse generator is required more and more higher. In this paper, it is realized by increasing the output power of the module while the output impedance of the module changes little. The module of the generator is based on pulse forming network (PFN) and linear transformer (LT). Four Blumlein PFNs with arc-type configuration and 24 Ω characteristic impedance were connected symmetrically to the primary coil of the LTD and driven by two identical laser triggered spark switches to ensure four Blumlein PFNs synchronizing operation. On this basis, a two-stage high-power pulse generator based on PFN-LT is developed. The following technical parameters of the generator were achieved on a 12 Ω high-power solid resistor: output voltage amplitude of ∼250 kV and output power of ∼5.2 GW at a repetition rate of 5 Hz.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"10 1","pages":"1-8"},"PeriodicalIF":0.9,"publicationDate":"2021-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82069285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaoyan Liu, D. Ba, Deqiang Jiao, Xiangxin Shao, Xingjun Mu, Ying Wang
The two-dimensional snake scanning of the CCD method provides an effective solution to measure small-scale light spots which are smaller than one CCD pixel. The influences of the A/D conversion digits and response uniformity of the CCD on the measurement error are studied. When the A/D conversion digit is 20, the measurement error can be ignored. The maximum error value of the nonuniform response of the CCD pixel when the order of the super-Gaussian function is 10 is 0.7 μm. The research results can be used to guide the experiment.
{"title":"Influences of Analog-to-Digital Conversion Accuracy and Response Uniformity of CCD on Small-Scale Laser Focal Spot Measurements","authors":"Xiaoyan Liu, D. Ba, Deqiang Jiao, Xiangxin Shao, Xingjun Mu, Ying Wang","doi":"10.1155/2021/6664228","DOIUrl":"https://doi.org/10.1155/2021/6664228","url":null,"abstract":"The two-dimensional snake scanning of the CCD method provides an effective solution to measure small-scale light spots which are smaller than one CCD pixel. The influences of the A/D conversion digits and response uniformity of the CCD on the measurement error are studied. When the A/D conversion digit is 20, the measurement error can be ignored. The maximum error value of the nonuniform response of the CCD pixel when the order of the super-Gaussian function is 10 is 0.7 μm. The research results can be used to guide the experiment.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":"11 1","pages":"1-8"},"PeriodicalIF":0.9,"publicationDate":"2021-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84840684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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