Energy Transformation Mechanism in the Solar Atmosphere Associated with Magnetofluid Coupling: Explosive and Eruptive Events

Ohsaki, Shuichi; Shatashvili, N. L.; Yoshida, Zensho; Mahajan, S. M.

doi:10.1086/339499

Cited by 46 publications

(53 citation statements)

References 34 publications

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“…(8)(9). Because this system, in its non-degenerate form, has been highly studied ( [7,9,10,14,41] and references therein), we can safely draw interesting inferences about: 1) Some distinguishing features of the expected "degeneracy-modified" solutions and even the significance and possible applications of somewhat straightforward extensions of these solutions (keeping electron inertia and adding gravity, for example). Several of these general features have already discussed.…”

Section: Modelmentioning

confidence: 98%

Beltrami–Bernoulli equilibria in plasmas with degenerate electrons

2015

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A new class of Double Beltrami-Bernoulli equilibria, sustained by electron degeneracy pressure, are investigated. It is shown that due to electron degeneracy, a nontrivial Beltrami-Bernoulli equilibrium state is possible even for a zero temperature plasma. These states are, conceptually, studied to show the existence of new energy transformation pathways converting, for instance, the degeneracy energy into fluid kinetic energy. Such states may be of relevance to compact astrophysical objects like white dwarfs, neutron stars etc.

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Section: Modelmentioning

confidence: 98%

Beltrami–Bernoulli equilibria in plasmas with degenerate electrons

2015

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“…It can undergo a catastrophe converting magnetic energy into kinetic energy, thus, simulating one of the defining features of an eruptive event. Ohsaki et al (2002, henceforth OSYM) found that a sequence of slowly varying DB equilibria constrained by the invariants can, indeed, terminate in a catastrophe; at the catastrophe boundary, the amplitude of the small scale vanishes tending to (formally) becoming imaginary. OSYM found that the removal of the small scale can occur if the system energy exceeds a critical energy determined by the two helicities: …”

Section: Double Beltrami Statesmentioning

confidence: 99%

Application of Double Beltrami states to solar eruptions

Kagan¹,

Mahajan²

2010

Monthly Notices of the Royal Astronomical Society

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We show that the general class of Double Beltrami (DB) states, which are the lowest energy equilibria of Hall magnetohydrodynamics, can have characteristics similar to those of active regions in the solar corona and is capable of undergoing a catastrophe that can cause a solar eruption, such as a flare or coronal mass ejection (CME). We then show that the qualitative evolution of the DB state is consistent with that of a solar eruption. Finally, we make two quantitative comparisons of DB states to CMEs, which are the simplest result of the catastrophe. First, we show that the DB expansion by a factor of 1–2 before the catastrophe is consistent with the increase in the height of the leading edges of Large‐Angle Spectrometric Coronagraph (LASCO C1) CMEs in the quasi‐equilibrium stage. Secondly, we use the assumption that DB states are randomly chosen from the allowed phase space of coronal structures to predict that the probability of a coronal structure erupting is 0.046. Identifying active regions with DB states and using observational constraints to estimate that the state is replaced every 60 min by emerging loops results in a CME rate of 11 d−1, which is in reasonable agreement with the actual rate of about 6 d−1 at solar maximum.

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“…The latter mechanism requires a detailed time-dependent treatment. The semi-equilibrium, collisionless magnetofluid treatment pertains only to the former case (Ohsaki et al 2001;Ohsaki et al 2002). In the references cited, the conditions for catastrophic transformations of an original DB (double Beltrami state) were investigated.…”

Section: Quasi-equilibrium Pathway Of Flow Acceleration Due To Magnetmentioning

confidence: 99%

Generation of Flows in the Solar Atmosphere Due to Magnetofluid Coupling

Mahajan

Nikol’skaya

Shatashvili

et al. 2002

The Astrophysical Journal

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Within the framework of a two-fluid description possible pathways for the generation of fast flows (dynamical as well as steady) in the lower solar atmosphere is established. It is shown that a primary plasma flow (locally sub-Alfvénic) is accelerated when interacting with emerging/ambient arcade-like closed field structures. The acceleration implies a conversion of thermal and field energies to kinetic energy of the flow. The time-scale for creating reasonably fast flows ( 100 km/s) is dictated by the initial ion skin depth while the amplification of the flow depends on local β. It is shown, for the first time, that distances over which the flows become "fast" are ∼ 0.01 R s from the interaction surface; later the fast flow localizes (with dimensions 0.05 R S ) in the upper central region of the original arcade. For fixed initial temperature the final speed ( 500 km/s) of the accelerated flow, and the modification of the field structure are independent of the time-duration (life-time) of the initial flow. In the presence of dissipation, these flows are likely to play a fundamental role in the heating of the finely structured Solar atmosphere.

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Energy Transformation Mechanism in the Solar Atmosphere Associated with Magnetofluid Coupling: Explosive and Eruptive Events

Cited by 46 publications

References 34 publications

Beltrami–Bernoulli equilibria in plasmas with degenerate electrons

Beltrami–Bernoulli equilibria in plasmas with degenerate electrons

Application of Double Beltrami states to solar eruptions

Generation of Flows in the Solar Atmosphere Due to Magnetofluid Coupling

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