ENERGY PRINCIPLE;
RECONNECTION;
PLASMA;
TURBULENCE;
CLOUDS;
DECAY;
D O I:
10.1063/5.0059756
中图分类号:
O35 [流体力学];
O53 [等离子体物理学];
学科分类号:
070204 ;
080103 ;
080704 ;
摘要:
Plasma relaxation in the presence of an initially braided magnetic field can lead to self-organization into relaxed states that retain non-trivial magnetic structure. These relaxed states may be in conflict with the linear force-free fields predicted by the classical Taylor theory, and remain to be fully understood. Here, we study how the individual field line helicities evolve during such a relaxation, and show that they provide new insights into the relaxation process. The line helicities are computed for numerical resistive-magnetohydrodynamic simulations of a relaxing braided magnetic field with line-tied boundary conditions, where the relaxed state is known to be non-Taylor. First, our computations confirm recent analytical predictions that line helicity will be predominantly redistributed within the domain, rather than annihilated. Second, we show that self-organization into a relaxed state with two discrete flux tubes may be predicted from the initial line helicity distribution. Third, for this set of line-tied simulations we observe that the sub-structure within each of the final tubes is a state of uniform line helicity. This uniformization of line helicity is consistent with Taylor theory applied to each tube individually. However, it is striking that the line helicity becomes significantly more uniform than the force-free parameter.
机构:
United Arab Emirates Univ, Phys Dept, POB 15551, Al Ain, U Arab EmiratesUniv St Andrews, Sch Phys & Astron, SUPA, St Andrews KY16 9SS, Fife, Scotland
机构:
United Arab Emirates Univ, Phys Dept, POB 15551, Al Ain, U Arab EmiratesUniv St Andrews, Sch Phys & Astron, SUPA, St Andrews KY16 9SS, Fife, Scotland
机构:
Inst Solar Terr Phys, POB 291,Lermontov St 126a, Irkutsk 664033, RussiaInst Solar Terr Phys, POB 291,Lermontov St 126a, Irkutsk 664033, Russia
Pipin, Valery V.
Pevtsov, Alexei A.
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机构:
Natl Solar Observ, 3665 Discovery Dr,3rd Floor, Boulder, CO 80303 USA
RAS Pulkovo, Cent Astron Observ, St Petersburg 196140, RussiaInst Solar Terr Phys, POB 291,Lermontov St 126a, Irkutsk 664033, Russia
Pevtsov, Alexei A.
Liu, Yang
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h-index: 0
机构:
Stanford Univ, Stanford, CA 94305 USAInst Solar Terr Phys, POB 291,Lermontov St 126a, Irkutsk 664033, Russia
Liu, Yang
Kosovichev, Alexander G.
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h-index: 0
机构:
New Jersey Inst Technol, Newark, NJ 07102 USAInst Solar Terr Phys, POB 291,Lermontov St 126a, Irkutsk 664033, Russia
机构:
New Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USANew Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA
Jing, Ju
Park, Sung-Hong
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h-index: 0
机构:
Korea Astron & Space Sci Inst, Taejon 305348, South KoreaNew Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA
Park, Sung-Hong
Liu, Chang
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h-index: 0
机构:
New Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USANew Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA
Liu, Chang
Lee, Jeongwoo
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h-index: 0
机构:
New Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA
Kyung Hee Univ, Sch Space Res, Yongin 446701, South KoreaNew Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA
Lee, Jeongwoo
Wiegelmann, Thomas
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机构:
Max Planck Inst Sonnensyst Forsch MPS, D-37191 Katlenburg Lindau, GermanyNew Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA
Wiegelmann, Thomas
Xu, Yan
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h-index: 0
机构:
New Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USANew Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA
Xu, Yan
Deng, Na
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h-index: 0
机构:
New Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USANew Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA
Deng, Na
Wang, Haimin
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h-index: 0
机构:
New Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USANew Jersey Inst Technol, Space Weather Res Lab, Newark, NJ 07102 USA