Explosive heating of low-density coronal plasma

被引：0

作者：

Bradshaw, S.J. ^{[1
]}

Cargill, P.J. ^{[1
]}

机构：

[1] Space and Atmospheric Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2BZ, United Kingdom

来源：

Astronomy and Astrophysics | 1600年 / 458卷 / 03期

关键词：

Context. This paper addresses the impulsive heating of very diffuse coronal loops; such as can occur in a nanoflare-heated corona with low filling factor. Aims. We study the physics associated with nanoflare heating in this scenario and aim to determine whether there exist any observable signatures. Methods. We derive an analytical model in order to gain some simple physical insights into the system and use a one dimensional hydrodynamic model that treats the electrons and ions as a coupled fluid to simulate nanoflare heating with time-scales of 30 s. Our analytical model also provide a means of verifying our numerical results. Results. We find that diffuse loops containing plasma at T > 20 MK can be rapidly created and subsequently filled by the violent evaporation of chromospheric plasma driven by near-saturated thermal conduction. Most importantly; we find order-of-magnitude departures from equilibrium of the ionisation balance for iron and use this result to identify a potential signature of this heating mechanism. Conclusions. We conclude that nanoflare heating can account for the presence of extremely high temperature plasma in a corona with low filling factor. We find that near-saturated thermal conduction may play a key role at the onset of chromospheric evaporation and a non-equilibrium ionisation balance is absolutely inevitable. The high temperatures could never be directly measured in the corona due to the small emission measure and the most promising signature of such heating is blue-shifted plasma from the loop footpoints. We find reason for cautious optimism that this signature can be detected by future space-based spectroscopic instrumentation (e.g. SolarB-EIS). © ESO 2006;

D O I：

暂无

中图分类号：

学科分类号：

摘要：

Journal article (JA)

引用

页码：987 / 995

共 50 条

[1] Explosive heating of low-density coronal plasma
Bradshaw, S. J.
Cargill, P. J.
ASTRONOMY & ASTROPHYSICS, 2006, 458 (03) : 987 - 995
[2] IONIZATION AND HEATING OF A LOW-DENSITY PLASMA BY ENERGETIC PARTICLES
ALDROVANDI, SM
PEQUIGNOT, D
ASTRONOMY & ASTROPHYSICS, 1973, 26 (01): : 33 - 43
[3] EXPLOSIVE INSTABILITY AND CORONAL HEATING
Dahlburg, R. B.
Liu, J. -H.
Klimchuk, J. A.
Nigro, G.
ASTROPHYSICAL JOURNAL, 2009, 704 (02): : 1059 - 1064
[4] HETEROGENEITY OF APOLIPOPROTEINS IN VERY LOW-DENSITY AND LOW-DENSITY PLASMA LIPOPROTEINS
PENN, A
SHORE, B
SHORE, V
FEDERATION PROCEEDINGS, 1977, 36 (03) : 432 - 432
[5] Loading of obstacles by explosion of a low-density sheet explosive
V. K. Golubev
V. A. Medvedkin
Journal of Applied Mechanics and Technical Physics, 2000, 41 (3) : 416 - 420
[6] PANFO: A novel low-density dry bulk explosive
Silva, G.
Orlandi, C. P.
PERFORMANCE OF EXPLOSIVES AND NEW DEVELOPMENTS, 2013, : 81 - 90
[7] OPEN MATRIX VERY LOW-DENSITY EXPLOSIVE FORMULATIONS
TULIS, AJ
AUSTING, JL
BAKER, DE
JOURNAL OF HAZARDOUS MATERIALS, 1982, 5 (04) : 387 - 391
[8] EXPLOSIVE EVENTS, MAGNETIC RECONNECTION, AND CORONAL HEATING
DERE, KP
SOLAR CORONA, 1993, 14 (04): : 13 - 22
[9] Ionization Transition in Low-Density Plasma
Triger, S. A.
Khomkin, A. L.
Shumikhin, A. S.
PLASMA PHYSICS REPORTS, 2011, 37 (09) : 816 - 822
[10] MIXING IN PLASMA AND LOW-DENSITY JETS
RUSS, S
STRYKOWSKI, PJ
PFENDER, E
EXPERIMENTS IN FLUIDS, 1994, 16 (05) : 297 - 307

← 1 2 3 4 5 →