-
超强激光与物质相互作用产生的超热电子在物质中输运产生Kα特征线辐射和轫致辐射.Kα辐射的对比度，即Kα特征线谱与其附近轫致辐射连续谱的强度比，依赖于轫致辐射的方向性，与超热电子的能量和传输相关.本文采用蒙特卡罗模拟研究了对超热电子束有准直作用的轴向匀强磁场和高斯分布环形磁场提高铜Kα辐射对比度的可能性.模拟和分析表明，轴向匀强磁场无法增强轫致辐射的方向性，不能有效提高Kα辐射的对比度.对于高斯分布环形磁场，当入射电子能谱具有玻尔兹曼分布时，由于含有大量低能电子且它们的轫致辐射方向性较差，Kα辐射对比度的增幅不大；而截掉低能部分的玻尔兹曼能谱电子束或能量较高的单能电子束入射时，高斯分布环形磁场能大幅提高沿入射电子束后向的Kα辐射对比度.对于能量为200-1000 keV范围的超热电子，峰值为100 T左右的环形磁场有利于提高Kα辐射的对比度.The interaction of a high intensity laser and a solid target generates a large number of hot electrons. When these hot electrons are transported in the target material, x-rays are produced, including Kα line and bremsstrahlung emissions. The contrast of Kα line emission, i.e., the intensity of Kα line relative to the intensity of bremsstrahlung continua around the Kα line, depends on the anisotropy of the bremsstrahlung emission and is related to the energy and transportation of the hot electrons. In the past, some researchers used axial or annular magnetic fields to collimate hot electrons, but whether these magnetic fields can enhance the contrast of Kα emission has not been studied. In the present work, the effect of an axially uniform magnetic field or an annular magnetic field with a Gaussian distribution on the contrast of Cu Kα emission is investigated by Monte Carlo simulations. The simulation results and analysis show that the axially uniform magnetic field cannot strengthen the anisotropy of the bremsstrahlung emission, so it cannot enhance the contrast of Kα emission efficiently. For the annular magnetic field with a Gaussian distribution, when an electron beam with a Boltzmann energy distribution is incident, due to the weak anisotropy of bremsstrahlung emission by low-energy electrons in the electron beam, the increase of Kα emission contrast is small. When an electron beam with a Boltzmann energy distribution, in which the low-energy part is cut off, or a mono-energetic electron beam is incident, the annular magnetic field with a Gaussian distribution significantly enhances the contrast of Kα emission in the back direction of the electron beam incidence. For an incident electron beam with an energy in the range of 200-1000 keV, an annular magnetic field with a Gaussian distribution and a peak value of approximately 100 T is optimal for enhancing the contrast of Kα emission. In consideration of existed experiments of producing annular magnetic fields and non-Boltzmann energy distribution hot electrons, it will be possible to generate higher contrast Kα emissions enhanced by magnetic fields in future experiments.
-
Keywords:
- Contrast of Kα emission /
- Bremsstrahlung emission /
- Magnetic field /
- Monte Carlo simulation
-
[1] Wen X L, Hong W, Gu Y Q, He Y L, Tang C M, Wang J 2007 High Power Laser and Particle Beams 19 1373 (in Chinese) [温贤伦，洪伟，谷渝秋，何颖玲，唐翠明，王剑 2007 强激光与粒子束 19 1373]
[2] Gambari M, Clady R, Stolidi A, Utéza O, Sentis M, Ferré A 2020 Sci. Rep. 10 6766
[3] Ivanov K A, Gavrilin I M, Volkov R V, Gavrilov S A, Savel Ev A B 2021 Laser Phys. Lett. 18 075401
[4] Sawada H, Lee S, Shiroto T, Nagatomo H, Arikawa Y, Nishimura H, Ueda T, Shigemori K, Sunahara A, Ohnishi N, Beg F N, Theobald W, Pérez F, Patel P K, Fujioka S 2016 Appl. Phys. Lett. 108 254101
[5] Park H S, Chambers D M, Chung H K, Clarke R J, Eagleton R, Giraldez E, Goldsack T, Heathcote R, Izumi N, Key M H, King J A, Koch J A, Landen O L, Nikroo A, Patel P K, Price D F, Remington B A, Robey H F, Snavely R A, Steinman D A, Stephens R B, Stoeckl C, Storm M, Tabak M, Theobald W, Town R P J, Wickersham J E, Zhang B B 2006 Phys. Plasmas 13 056309
[6] Kritcher A L, Neumayer P, Castor J, Döppner T, Falcone R W, Landen O L, Lee H J, Lee R W, Holst B, Redmer R, Morse E C, Ng A, Pollaine S, Price D, Glenzer S H 2009 Phys. Plasmas 16 056308
[7] Westover B, MacPhee A, Chen C, Hey D, Ma T, Maddox B, Park H S, Remington B, Beg F N 2010 Phys. Plasmas 17 082703
[8] Chen L M, Kando M, Xu M H, Li Y T, Koga J, Chen M, Xu H, Yuan X H, Dong Q L, Sheng Z M, Bulanov S V, Kato Y, Zhang J, Tajima T 2008 Phys. Rev. Lett. 100 045004
[9] Cai J J, Huang W Z, Gu Y Q, Dong K G, Wu Y C, Zhu B, Wang X F 2011 High Power Laser and Particle Beams 23 1082 (in Chinese) [蔡涓涓, 黄文忠, 谷渝秋, 董克攻, 吴玉迟, 朱斌, 王晓方 2011 强激光与粒子束 23 1082]
[10] Azamoum Y, Tcheremiskine V, Clady R, Ferré A, Charmasson L, Utéza O, Sentis M 2018 Sci. Rep. 8 4119
[11] Tillman C, Mercer I, Svanberg S, Herrlin K 1996 J. Opt. Soc. Am. B 13 209
[12] Lu Z W, Wang X F 2019 Acta Phys. Sin. 68 035202 (in Chinese) [陆中伟, 王晓方 2019 物理学报 68 035202]
[13] Lévy A, Dorchies F, Audebert P, Chalupský J, Hájková V, Juha L, Kaempfer T, Sinn H, Uschmann I, Vyšín L, Gaudin J 2010 Appl. Phys. Lett. 96 151114
[14] Wang R R, An H H, Xie Z Y, Wang W 2018 Phys. Plasmas 25 053303
[15] Wang R R, Chen W M, Dong J Q, Xiong J, Fu S Z 2008 Acta Opt. Sin. 28 1220-1224 (in Chinese) [王瑞荣, 陈伟民, 董佳钦, 熊俊, 傅思祖 2008 光学学报 28 1220]
[16] Zhao J C, Zheng J H, Cao L H, Zhao Z Q, Li S, Gu Y Q, Liu J 2016 Phys. Plasmas 23 093102
[17] Yoshioka A, Yamaguchi Y, Tamura K, Shimizu R 2004 Surf. Interface Anal. 36 1417
[18] Xu M H, Liang T J, Zhang J 2006 Acta Phys. Sin. 55 2357 (in Chinese) [徐妙华, 梁天骄, 张杰 2006 物理学报 55 2357]
[19] Xiao Y Y, Wang X F 2024 Phys. Plasmas 31 073302
[20] Cai D F, Wang L J, Wang J, Zheng Z J 2009 J. At. Mol. Phys. 26 535 (in Chinese) [蔡达锋, 王利娟, 王剑, 郑志坚 2009 原子与分子物理学报 26 535]
[21] Bailly-Grandvaux M, Santos J J, Bellei C, Forestier-Colleoni P, Fujioka S, Giuffrida L, Honrubia J J, Batani D, Bouillaud R, Chevrot M, Cross J E, Crowston R, Dorard S, Dubois J L, Ehret M, Gregori G, Hulin S, Kojima S, Loyez E, Marquès J R, Morace A, Nicolaï P, Roth M, Sakata S, Schaumann G, Serres F, Servel J, Tikhonchuk V T, Woolsey N, Zhang Z 2018 Nat. Commun. 9 102
[22] Malko S, Vaisseau X, Perez F, Batani D, Curcio A, Ehret M, Honrubia J, Jakubowska K, Morace A, Santos J J, Volpe L 2019 Sci. Rep. 9 14061
[23] Xu H, Yang X H, Sheng Z M, McKenna P, Ma Y Y, Zhuo H B, Yin Y, Ren C, Zhang J 2019 Nucl. Fusion 59 126024
[24] Reich Ch, Gibbon P, Uschmann I, Förster E 2000 Phys. Rev. Lett. 84 4846
[25] Šmíd M, Renner O, Colaitis A, Tikhonchuk V T, Schlegel T, Rosmej F B 2019 Nat. Commun. 10 4212
[26] Khattak F Y, Garcia Saiz E, Gibbon P, Karmakar A, Dzelzainis T W J, Lewis C L S, Robinson A P L, Zepf M, Riley D 2012 Eur. Phys. J. D 66 298
[27] Salvat F, Fernández-Varea J, Sempau J 2008 PENELOPE-2008, A Code System for Monte Carlo Simulation of Electron and Photon Transport (Issy-les-Moulineau: OECD/NEA Data Bank)
[28] Li B Y, Tian C, Zhang Z M, Zhang F, Shan L Q, Zhang B, Zhou W M, Zhang B H, Gu Y Q 2016 Phys. Plasmas 23 093121
[29] Green J S, Ovchinnikov V M, Evans R G, Akli K U, Azechi H, Beg F N, Bellei C, Freeman R R, Habara H, Heathcote R, Key M H, King J A, Lancaster K L, Lopes N C, Ma T, MacKinnon A J, Markey K, McPhee A, Najmudin Z, Nilson P, Onofrei R, Stephens R, Takeda K, Tanaka K A, Theobald W, Tanimoto T, Waugh J, Van Woerkom L, Woolsey N C, Zepf M, Davies J R, Norreys P A 2008 Phys. Rev. Lett. 100 015003
[30] Salzmann D, Reich C, Uschmann I, Förster E, Gibbon P 2002 Phys. Rev. E 65 036402
[31] Toncian T, Wang C, McCary E, Meadows A, Arefiev A V, Blakeney J, Serratto K, Kuk D, Chester C, Roycroft R, Gao L, Fu H, Yan X Q, Schreiber J, Pomerantz I, Bernstein A, Quevedo H, Dyer G, Ditmire T, Hegelich B M 2016 Matter Radiat. Extremes 1 82
[32] Roet D, Ceballos C, Van Espen P 2006 Nucl. Instrum. Methods Phys. Res. B 251 317
[33] Braenzel J, Andreev A A, Abicht F, Ehrentraut L, Platonov K, Schnurer M 2017 Phys. Rev. Lett. 118 014801
计量
- 文章访问数: 28
- PDF下载量: 2
- 被引次数: 0
下载:
