Characteristics of heat flux and electromagnetic electron-cyclotron instabilities driven by solar wind electrons

被引:15
作者
Saeed, Sundas [1 ,2 ]
Yoon, P. H. [2 ,3 ]
Sarfraz, M. [1 ,2 ]
Qureshi, M. N. S. [1 ]
机构
[1] GC Univ Lahore, Dept Phys, Katchery Rd, Lahore 54000, Pakistan
[2] Univ Maryland, Dept IPST, College Pk, MD 20742 USA
[3] Kyung Hee Univ, Sch Space Res, Yongin 446701, Gyeonggi Do, South Korea
基金
新加坡国家研究基金会; 美国国家科学基金会;
关键词
instabilities; plasmas; methods: analytical; solar wind; KEV SUPERHALO ELECTRONS; DISTRIBUTIONS; POPULATIONS; ANISOTROPY; NETWORK; PLASMA; KAPPA; CORE;
D O I
10.1093/mnras/stx049
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
In situ observations reveal the existence of electron velocity distribution function in the solar wind, where the net distribution can be modelled by a combination of core, halo and strahl. These components often possess a relative drift and with respective temperature anisotropies. The relative drift between the core and halo components leads to heat flux (HF) instability, while temperature anisotropies drive electromagnetic electron-cyclotron (EMEC) instability. These instabilities have been separately studied in the literature, but for the first time, the present study combines both unstable modes in the presence of two free energy sources, namely, excessive parallel pressure and excessive perpendicular temperature. HF instability (which is a left-hand circularly polarized mode) is effectively similar to electron firehose instability, except that the free energy is provided by net relative drift among two component electrons in the background of protons. The HF instability is discussed here along with (the right-hand polarized) EMEC instability driven by temperature anisotropy. The unstable HF mode is conventionally termed the `whistler' HF instability, but it is actually polarized in the opposite sense to the whistler wave. EMEC mode, on the other hand, reduces to the proper whistler wave in the absence of free energy source. The present combined analysis clarifies the polarization characteristics of these two modes in an unambiguous manner.
引用
收藏
页码:4928 / 4936
页数:9
相关论文
共 32 条
[1]   THE ORIGIN OF NON-MAXWELLIAN SOLAR WIND ELECTRON VELOCITY DISTRIBUTION FUNCTION: CONNECTION TO NANOFLARES IN THE SOLAR CORONA [J].
Che, H. ;
Goldstein, M. L. .
ASTROPHYSICAL JOURNAL LETTERS, 2014, 795 (02)
[2]   SOLAR-WIND ELECTRONS [J].
FELDMAN, WC ;
ASBRIDGE, JR ;
BAME, SJ ;
MONTGOMERY, MD ;
GARY, SP .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1975, 80 (31) :4181-4196
[3]   INSTABILITIES ASSOCIATED WITH HEAT CONDUCTION IN SOLAR WIND AND THEIR CONSEQUENCES [J].
FORSLUND, DW .
JOURNAL OF GEOPHYSICAL RESEARCH, 1970, 75 (01) :17-+
[4]  
Fried B. D., 1961, PLASMA DISPERSION FU
[5]   ELECTROMAGNETIC ELECTRON-BEAM INSTABILITIES - HOT, ISOTROPIC BEAMS [J].
GARY, SP .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1985, 90 (NA11) :815-822
[6]   Solar wind electrons: Parametric constraints [J].
Gary, SP ;
Neagu, E ;
Skoug, RM ;
Goldstein, BE .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1999, 104 (A9) :19843-19849
[7]   SOLAR-WIND HEAT-FLUX REGULATION BY WHISTLER INSTABILITY [J].
GARY, SP ;
FELDMAN, WC .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1977, 82 (07) :1087-1094
[8]   Whistler heat flux instability at high beta [J].
Gary, SP ;
Li, H .
ASTROPHYSICAL JOURNAL, 2000, 529 (02) :1131-1135
[9]   ELECTRON HEAT-FLUX INSTABILITIES IN SOLAR-WIND [J].
GARY, SP ;
FELDMAN, WC ;
FORSLUND, DW ;
MONTGOMERY, MD .
GEOPHYSICAL RESEARCH LETTERS, 1975, 2 (03) :79-82
[10]   Solar wind outflow and the chromospheric magnetic network [J].
Hassler, DM ;
Dammasch, IE ;
Lemaire, P ;
Brekke, P ;
Curdt, W ;
Mason, HE ;
Vial, JC ;
Wilhelm, K .
SCIENCE, 1999, 283 (5403) :810-813