Plasmoids and Resulting Blobs due to the Interaction of Magnetoacoustic Waves with a 2.5D Magnetic Null Point

Context. Magnetohydrodynamic (MHD) waves have significant potential as a plasma heating mechanism. Finding a suitable wave dissipation mechanism is a very tough task, given the many observational constraints on the models, and this has resulted in the development of an important research community in solar physics. The magnetic field structure has an important role in the solar corona heating. Here, we investigate in detail current sheet mode generation via magnetic reconnection and mode conversion releases some of the free magnetic energy and produces heating. In addition, energy conversion is discussed completely. Moreover, nonlinear effects on density variations and, in turn, mode conversion are pursued. Aims. In order to assess the role of magnetoacoustic waves in plasma heating, we have modeled in detail a fast magneto-acoustic wave pulse near a magnetic null-point in a finite plasma-β. The behavior of the propagation and dissipation of the fast magneto-acoustic wave is investigated in the inhomogeneous magnetically structured solar corona. Particular attention is given to the dissipation of waves and coronal heating and energy transfer in the solar corona, focusing on the energy transfer resulting from the interaction of fast magneto-acoustic waves with 2.5D magnetic null-points. Methods. The shock−capturing Godunov−type PLUTO code was used to solve the ideal MHD set of equations in the context of wave-plasma energy transfer. Results. It is shown that magneto-acoustic waves could be a viable candidate to contribute significantly to the heating of the solar corona and maintain the solar corona at a temperature of a few million degrees. The temperature is not constant in the corona. Coronal heating occurs near magnetic null points. It is found that magnetic reconnection, phase mixing and mode conversion contribute to the heating. Moreover, nonlinear fast and slow magnetoacoustic waves are decoupled except in β = 1 layer.

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Magnetoacoustic Waves in a Stratified Atmosphere with a Magnetic Null Point

The Astrophysical Journal ◽

10.3847/1538-4357/aa5e4e ◽

2017 ◽

Vol 837 (1) ◽

pp. 94 ◽

Cited By ~ 13

Author(s):

Lucas A. Tarr ◽

Mark Linton ◽

James Leake

Keyword(s):

Null Point ◽

Magnetoacoustic Waves ◽

Magnetic Null ◽

Magnetic Null Point

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Cluster Observation of Electrostatic Solitary Waves around Magnetic Null Point in Thin Current Sheet

Chinese Physics Letters ◽

10.1088/0256-307x/27/1/019401 ◽

2010 ◽

Vol 27 (1) ◽

pp. 019401 ◽

Cited By ~ 7

Author(s):

Li Shi-You ◽

Deng Xiao-Hua ◽

Zhou Meng ◽

Yuan Zhi-Gang ◽

Wang Jing-Fang ◽

...

Keyword(s):

Current Sheet ◽

Solitary Waves ◽

Null Point ◽

Thin Current Sheet ◽

Magnetic Null ◽

Magnetic Null Point

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Quasi-periodic Radio Bursts Associated with Fast-mode Waves near a Magnetic Null Point

The Astrophysical Journal ◽

10.3847/1538-4357/aa7d53 ◽

2017 ◽

Vol 844 (2) ◽

pp. 149 ◽

Cited By ~ 19

Author(s):

Pankaj Kumar ◽

Valery M. Nakariakov ◽

Kyung-Suk Cho

Keyword(s):

Null Point ◽

Radio Bursts ◽

Fast Mode ◽

Magnetic Null ◽

Magnetic Null Point

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Spatially Separated Electron and Proton Beams in a Simulated Solar Coronal Jet

The Astrophysical Journal ◽

10.3847/1538-4357/ac2e6d ◽

2021 ◽

Vol 923 (2) ◽

pp. 163

Author(s):

Ross Pallister ◽

Peter F. Wyper ◽

David I. Pontin ◽

C. Richard DeVore ◽

Federica Chiti

Keyword(s):

Particle Acceleration ◽

Particle Deposition ◽

Lower Boundary ◽

Impulsive Phase ◽

Null Point ◽

Solar Photosphere ◽

In Situ Observations ◽

Magnetic Null ◽

Magnetic Null Point

Abstract Magnetic reconnection is widely accepted to be a major contributor to nonthermal particle acceleration in the solar atmosphere. In this paper we investigate particle acceleration during the impulsive phase of a coronal jet, which involves bursty reconnection at a magnetic null point. A test-particle approach is employed, using electromagnetic fields from a magnetohydrodynamic simulation of such a jet. Protons and electrons are found to be accelerated nonthermally both downwards toward the domain’s lower boundary and the solar photosphere, and outwards along the axis of the coronal jet and into the heliosphere. A key finding is that a circular ribbon of particle deposition on the photosphere is predicted, with the protons and electrons concentrated in different parts of the ribbon. Furthermore, the outgoing protons and electrons form two spatially separated beams parallel to the axis of the jet, signatures that may be observable in in-situ observations of the heliosphere.

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Plasma Flow Generation due to the Nonlinear Alfvén Wave Propagation around a 3D Magnetic Null Point

The Astrophysical Journal ◽

10.3847/1538-4357/ac242d ◽

2021 ◽

Vol 922 (2) ◽

pp. 123

Author(s):

S. Sabri ◽

H. Ebadi ◽

S. Poedts

Keyword(s):

Plasma Flow ◽

Current Density ◽

Flow Behavior ◽

Plasma Pressure ◽

Null Point ◽

Oscillatory Behavior ◽

Alfven Wave ◽

Plasma Energy ◽

Magnetic Null ◽

Magnetic Null Point

Abstract The behavior of current density accumulation around the sharp gradient of magnetic field structure or a 3D magnetic null point and with the presence of finite plasma pressure is investigated. It has to be stated that in this setup, the fan plane locates at the xy plane and the spine axis aligns along the z-axis. Current density generation in presence of the plasma pressure that acts as a barrier for developing current density is less well understood. The shock-capturing Godunov-type PLUTO code is used to solve the magnetohydrodynamic set of equations in the context of wave-plasma energy transfer. It is shown that propagation of Alfvén waves in the vicinity of a 3D magnetic null point leads to current density excitations along the spine axis and also around the magnetic null point. Besides, it is pointed out the x component of current density has oscillatory behavior while the y and z components do not show this property. It is plausible that it happens because the fan plane encompasses separating unique topological regions, while the spine axis does not have this characteristic and is just a line without separate topological regions. Besides, current density generation results in plasma flow. It is found that the y component of the current density defines the x component of the plasma flow behavior, and the x component of the current density prescribes the behavior of the y component of the plasma flow.

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