-
太阳辐射层与对流层边界区域(T ~ 180 eV,ne ~ 9 × 1022 cm-3)是太阳内部能量传输方式从辐射主导向对流主导转变的关键界面，也是研究高温稠密等离子体物理的天然实验室.这一区域的物理特性决定了恒星演化模型的可靠性与能量传输机制的稳定性，特别是高温稠密等离子体中强烈的碰撞电离会改变电子数密度分布，进而影响能量的输运过程.本文发展了一种耦合等离子体环境效应来计算原子结构的新方法：通过将计算原子结构的Flexible Atomic Code (FAC)与超网链(Hypernetted-chain,HNC)近似相结合，在原子波函数计算中引入电子-电子、电子-离子关联函数来考虑等离子体中屏蔽效应，系统研究了极端条件下电子碰撞电离的物理机制.基于扭曲波近似的计算表明，考虑等离子体环境效应时，碳、氮和氧元素的电子碰撞电离截面较自由原子模型显著增强，同时电离阈值出现明显下降的现象.研究发现这种增强效应主要源于离子间强耦合导致的原子势场重叠和自由电子屏蔽引起的束缚态能级移动.本研究直接将离子结构引入电子结构计算的哈密顿量中，所获得的电离参数可直接用于改进太阳内部辐射输运模型，为惯性约束聚变等极端条件等离子体研究提供理论支持.The boundary region between the solar radiation zone and the convection zone (T ~ 180 eV, ne ~ 9×1022 cm-3) is a critical interface where energy transport in the solar interior transitions from radiationdominated to convection-dominated regimes. This region also serves as a natural laboratory for studying hot dense plasma. The physical properties of this zone are essential for the reliability of stellar evolution models and the stability of energy transport mechanisms. One of major unresolved issue is how electron collision ionization affects the density of free electrons and radiation properties in this plasma, while accurately describing the impact of hot-dense environments on electron impact ionization (EII) (such as electron screening, ion correlation). To fill this gap, we systematically calculate EII cross sections for C, N, and O ions under realistic solar boundary conditions, with a focus on hot-dense environment impacts. We develop a novel computational framework that merges hot-dense environment effects into atomic structure calculations: the Flexible Atomic Code (FAC) for atomic structure is combined with the Hypernetted-Chain (HNC) approximation to capture electron–electron, electron–ion and ion-ion correlations, enabling self-consistent treatment of electron screening and ion correlation. Atomic wave functions are derived by solving the Dirac equation within the ion-sphere model, using a modified central potential that incorporates both free-electron screening and ion–ion interactions. EII cross sections are then computed via the Distorted-Wave (DW) approximation in FAC. The results demonstrate that hot-dense environment effects significantly enhance the electron-impact ionization cross sections of C, N, and O compared to those calculated under the free-atom model. Additionally, a notable reduction in the ionization threshold energy is observed. These effects are attributed to the overlap of atomic potentials due to strong ion coupling and the shift in bound-state energy levels caused by free-electron screening. For instance, under solar boundary conditions, the ionization cross section of C+ increased by up to 50%, with the ionization threshold decreasing from about 24 eV (isolated) to 18 eV (with screening). Similar enhancements were observed for nitrogen and oxygen ions across various charge states. By providing updated ionization cross sections for C, N, and O ions under realistic solar interior conditions, this work offers essential parameters for improving radiation transport models, ionization balance calculations, and equation-of-state models in stellar interiors. The results underscore the necessity of including hot-dense environment effects in atomic process calculations for hot dense plasmas, with implications for astrophysics and inertial confinement fusion research.
-
Keywords:
- radiation/convection zone boundary /
- environment effect /
- electron impact ionization /
- hypernetted-chain approximation
-
[1] Guenther D B, Demarque P, Kim Y C, Pinsonneault M H 1992 ApJ 387 372
[2] Bahcall J N, Ulrich R K 1988 Rev. Mod. Phys. 60 297
[3] Basu S, Grevesse N, Mathis S, Turck-Chieze S 2015 Space Sci. Rev. 196 49
[4] Bailey J E, Nagayama T, Loisel G P, Rochau G A, Blancard C, Colgan J, et al. 2015 Nature 517 56
[5] Fogle M, Bahati E M, Bannister M E, Vane C R, Loch S D, Pindzola M S, Ballance C P, Thomas R D, Zhaunerchyk V, Bryans P, Mitthumsiri W, Savin D W 2008 Astrophys. J. Suppl. Ser. 175 543
[6] Woodruff P R, Hublet M C, Harrison M F A, Brook E 1978 J. Phys. B: At. Mol. Opt. Phys. 11 L679
[7] Falk R A, Stefani G, Camilloni R, Dunn G H, Phaneuf R A, Gregory D C, Crandall D H 1983 Phys. Rev. A 28 91
[8] Loch S D, Witthoeft M, Pindzola M S, Bray I, Fursa D V, Fogle M, Schuch R, Glans P, Ballance C P, Griffin D C 2005 Phys. Rev. A 71 012716
[9] Loch S D, Colgan J, Pindzola M S, Westermann M, Scheuermann F, Aichele K, Hathiramani D, Salzborn E 2003 Phys. Rev. A 67 042714
[10] Alna’washi G A, Aryal N B, Baral K K, Thomas C M, Phaneuf R A, 2014 J. Phys. B: At. Mol. Opt. Phys. 47 135203
[11] Ludlow J A, Ballance C P, Loch S D, Pindzola M S, Griffin D C, 2009 Phys. Rev. A 79 032715
[12] Bray I, McNamara K, Fursa D V 2015 Phys. Rev. A 92 022705
[13] Fontes C J, Sampson D H, Zhang H L 1993 Phys. Rev. A 48 1975
[14] Kim Y K, Rudd M E 1994 Phys. Rev. A 50 3954
[15] Ma L L, Zhang S P, Zhang F J, Li M J, Jiang J, Ding X B, Jie L Y, Zhang D H, Dong C Z 2024 Acta Phys. Sin. 73 136 (in Chinese) [马莉莉，张世平，张芳军，李麦娟，蒋军，丁晓彬，颉录有， 张登红，董晨钟 2005 73 136]
[16] Kritcher A L, Swift D C, Döppner T, Bachmann B, Benedict L X, Collins G W, et al. 2020 Nature 584 51
[17] Giammichele N, Charpinet S, Fontaine G, Brassard P, Green E M, Van Grootel V, et al. 2018 Nature 554 73
[18] Bethkenhagen M, Witte B B L, Schörner M, Röpke G, Döppner T, Kraus D, Glenzer S H, Sterne P A, Redmer R 2020 Phys. Rev. Res. 2 023260
[19] Hurricane O A, Callahan D A, Casey D T, Celliers P M, Cerjan C, Dewald E L, et al. 2014 Nature 506 343
[20] Seddon E A, Clarke J A, Dunning D J, Masciovecchio C, Milne C J, Parmigiani F, Rugg D, Spence J C H, Thompson N R, Ueda K, Vinko S M, Wark J S, Wurth W 2017 Rep. Prog. Phys. 80 115901
[21] Vinko S M, Ciricosta O, Cho B I, Engelhorn K, Chung H K, Brown C R D, et al. 2012 Nature 482 59
[22] Ciricosta O, Vinko S M, Chung H K, Cho B I, Brown C R D, Burian T, et al. 2012 Phys. Rev. Lett. 109 065002
[23] Cho B I, Engelhorn, K Vinko S M, Chung, H K, Ciricosta O, Rackstraw D S, et al. 2012 Phys. Rev. Lett. 109 245003
[24] Van den Berg Q Y, Fernandez-Tello E V, Burian T, Chalupský J, Chung H K, Ciricosta1 O, Dakovski G L, et al. 2018 Phys. Rev. Lett. 120 055002
[25] Jung Y D, Yoon J S 1996 J. Phys. B: At. Mol. Opt. Phys. 29 3549
[26] Jung Y D 1998 Phys. Plasma. 5 536
[27] Li B W, Jang J, Dong C Z, Wang J G, Ding X B 2009 Acta Phys. Sin. 58 5274 (in Chinese) [李博 文，蒋军，董晨钟，王建国，丁晓彬 2009 58 5274]
[28] Johnson W R, Nilsen J, Cheng K T 2024 High Energ Density Phys. 53 101153
[29] Zeng J, Ye C, Liu P, Gao C, Li Y, Yuan J 2022 Int. J. Mol. Sci 23 6033
[30] Zhang P, J Y, Zan X, Liu P, Li Y, Gao C, Hou Y, Zeng J, Yuan J 2021 Phys. Rev. E 104 035204
[31] Bar-Shalom A, Klapisch M, Oreg J 1988 Phys. Rev. A 38 1773
[32] Gu M F 2008 Can. J. Phys. 86 675
[33] Wünsch K, Hilse P, Schlanges M, Gericke D O 2008 Phys. Rev. E 77 056404
[34] Bredow R, Bornath T, Kraeft W D, Redmer R 2013 Contrib. to Plasma Phys. 53 276
[35] Schwarz V, Bornath T, Kraeft W D, Glenzer S H, Höll A, Redmer R 2007 Contrib. to Plasma Phys. 47 324
[36] Bezkrovniy V, Schlanges M, Kremp D, Kraeft W D 2004 Phys. Rev. E 69 061204
[37] Baus M, Hansen J P 1980 Phys. Rep. 59 1
[38] Saumon D, Starrett C E, Kress J D, Clerouin J 2012 High Energy Density Phys. 8 150
[39] Hou Y, Bredow R, Yuan J M, Redmer R 2015 Phys. Rev. E 91 033114
[40] Hou Y, Fu Y S, Bredow R, Kang D, Redmer R, Yuan J 2017 High Energy Density Phys. 22 21
[41] Dharma-Wardana M W C, Taylor R 1981 J. Phys. C: Solid State Phys. 14 629
[42] Feynman R P, Metropolis N, Teller E 1949 Phys. Rev. 75 1561
[43] Thøgersen M, Zinner N T, Jensen A S 2009 Phys. Rev. A 80 043625
[44] Deutsch C 1977 Phys. Lett. A 60 317
[45] Wang Y 2020 Phys. Rev. Lett. 124 017002
[46] Jin Y, Zhang P, Li Y J, Hou Y, Zeng J L, Yuan J M 2021 Acta Phys. Sin. 70 91 (in Chinese) [金 阳, 张平, 李永军, 侯永, 曾交龙, 袁建民 2021 70 91 ]
[47] Zeng J L, Liu L P, Liu P F, Yuan J M 2014 Phys. Rev. A 90 044701
[48] Cowan R D 1981 The theory of atomic structure and spectra (California: University of California Press) pp214–236
[49] Gaigalas G, Rudzikas Z, Fischer C F 1997 J. Phys. B: At. Mol. Opt. Phys. 30 3747
[50] Bar-Shalom A, Klapisch M, Oreg J 1988 Phys. Rev. A 38 1773
[51] Mott N F 1930 Proc.R.Soc.Lond.A 126 259
[52] Vriens L 1969 Case studies in atomic collision physics (Vol. 1) (North-Holland Amsterdam: Press) p335
[53] Bethe H 1930 Ann. Phys. 397 325
[54] Gregory D C, Dittner P F, Crandall D H 1983 Phys. Rev. A 27 724
[55] Bannister M E 1996 Phys. Rev. A 54 1435
[56] Brouillard F, 2013 Atomic processes in electron-ion and ion-ion collisions (Vol. 145) (New York: Springer Science & Business Media Press) pp75–91
[57] Bartschat K 1998 Comput. phys. commun. 114 168
[58] Son S, Thiele R, Jurek Z, Ziaja B, and Santra R, 2014 Phys. Rev. X 4 031004
计量
- 文章访问数: 31
- PDF下载量: 0
- 被引次数: 0
下载:
