Test particle acceleration in resistive torsional fan magnetic reconnection using laboratory plasma parameters

2021 ◽  
Vol 87 (6) ◽  
Author(s):  
D.L. Chesny ◽  
N.B. Orange ◽  
K.W. Hatfield
Keyword(s):  
Particle Acceleration ◽  
Magnetic Reconnection ◽  
Three Dimensional ◽  
Laboratory Plasma ◽  
Plasma Parameters ◽  
Astrophysical Plasmas ◽  
Magnetic Field Topology ◽  
Reconnection Region ◽  
Fundamental Process ◽  
Technology Applications

Particle acceleration via magnetic reconnection is a fundamental process in astrophysical plasmas. Experimental architectures are able to confirm a wide variety of particle dynamics following the two-dimensional Sweet–Parker model, but are limited in their reproduction of the fan-spine magnetic field topology about three-dimensional (3-D) null points. Specifically, there is not yet an experiment featuring driven 3-D torsional magnetic reconnection. To move in this direction, this paper expands on recent work toward the design of an experimental infrastructure for inducing 3-D torsional fan reconnection by predicting feasible particle acceleration profiles. Solutions to the steady-state, kinematic, resistive magnetohydrodynamic equations are used to numerically calculate particle trajectories from a localized resistivity profile using well-understood laboratory plasma parameters. We confine a thin, 10 eV helium sheath following the snowplough model into the region of this localized resistivity and find that it is accelerated to energies of ${\approx }2$ keV. This sheath is rapidly accelerated and focused along the spine axis propagating a few centimetres from the reconnection region. These dynamics suggest a novel architecture that may hold promise for future experiments studying solar coronal particle acceleration and for technology applications such as spacecraft propulsion.

scholarly journals Theory of magnetic reconnection in solar and astrophysical plasmas

2012 ◽  
Vol 370 (1970) ◽  
pp. 3169-3192 ◽  
Author(s):  
David I. Pontin
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Astrophysical Plasmas ◽  
Current State ◽  
Fundamental Process ◽  
Recent Developments ◽  
The Magnetic Field ◽  
Theoretical Results

Magnetic reconnection is a fundamental process in a plasma that facilitates the release of energy stored in the magnetic field by permitting a change in the magnetic topology. In this paper, we present a review of the current state of understanding of magnetic reconnection. We discuss theoretical results regarding the formation of current sheets in complex three-dimensional magnetic fields and describe the fundamental differences between reconnection in two and three dimensions. We go on to outline recent developments in modelling of reconnection with kinetic theory, as well as in the magnetohydrodynamic framework where a number of new three-dimensional reconnection regimes have been identified. We discuss evidence from observations and simulations of Solar System plasmas that support this theory and summarize some prominent locations in which this new reconnection theory is relevant in astrophysical plasmas.

scholarly journals Three-dimensional magnetic reconnection in astrophysical plasmas

2021 ◽  
Vol 477 (2249) ◽  
Author(s):  
Ting Li ◽  
Eric Priest ◽  
Ruilong Guo
Keyword(s):  
Magnetic Reconnection ◽  
Solar Flares ◽  
Magnetic Energy ◽  
Three Dimensional ◽  
Particle Energy ◽  
Two Dimensions ◽  
Three Dimensions ◽  
New Paradigm ◽  
Astrophysical Plasmas ◽  
Fundamental Process

Magnetic reconnection is a fundamental process in laboratory, magnetospheric, solar and astrophysical plasmas, whereby magnetic energy is converted into heat, bulk kinetic energy and fast particle energy. Its nature in two dimensions is much better understood than that in three dimensions, where its character is completely different and has many diverse aspects that are currently being explored. Here, we focus on the magnetohydrodynamics of three-dimensional reconnection in the plasma environment of the Solar System, especially solar flares. The theory of reconnection at null points, separators and quasi-separators is described, together with accounts of numerical simulations and observations of these three types of reconnection. The distinction between separator and quasi-separator reconnection is a theoretical one that is unimportant for the observations of energy release. A new paradigm for solar flares, in which three-dimensional reconnection plays a central role, is proposed.

scholarly journals Onset of fast magnetic reconnection and particle energization in laboratory and space plasmas

2020 ◽  
Vol 86 (6) ◽  
Author(s):  
F. Pucci ◽  
M. Velli ◽  
C. Shi ◽  
K. A. P. Singh ◽  
A. Tenerani ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Magnetic Reconnection ◽  
Theoretical Models ◽  
Laboratory Plasma ◽  
Plasma Parameters ◽  
Astrophysical Plasmas ◽  
Plasma Dynamics ◽  
Laboratory Plasmas ◽  
Wide Range ◽  
Kinetic Effects

The onset of magnetic reconnection in space, astrophysical and laboratory plasmas is reviewed discussing results from theory, numerical simulations and observations. After a brief introduction on magnetic reconnection and approach to the question of onset, we first discuss recent theoretical models and numerical simulations, followed by observations of reconnection and its effects in space and astrophysical plasmas from satellites and ground-based detectors, as well as measurements of reconnection in laboratory plasma experiments. Mechanisms allowing reconnection spanning from collisional resistivity to kinetic effects as well as partial ionization are described, providing a description valid over a wide range of plasma parameters, and therefore applicable in principle to many different astrophysical and laboratory environments. Finally, we summarize the implications of reconnection onset physics for plasma dynamics throughout the Universe and illustrate how capturing the dynamics correctly is important to understanding particle acceleration. The goal of this review is to give a view on the present status of this topic and future interesting investigations, offering a unified approach.

Toward laboratory torsional spine magnetic reconnection

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
David L. Chesny ◽  
N. Brice Orange ◽  
Hakeem M. Oluseyi ◽  
David R. Valletta
Keyword(s):  
Magnetic Reconnection ◽  
Kinetic Parameters ◽  
Three Dimensional ◽  
Limited Range ◽  
Null Point ◽  
Plasma Parameters ◽  
Astrophysical Plasmas ◽  
Current Sheets ◽  
Practical Applications ◽  
Field Lines

Magnetic reconnection is a fundamental energy conversion mechanism in nature. Major attempts to study this process in controlled settings on Earth have largely been limited to reproducing approximately two-dimensional (2-D) reconnection dynamics. Other experiments describing reconnection near three-dimensional null points are non-driven, and do not induce any of the 3-D modes of spine fan, torsional fan or torsional spine reconnection. In order to study these important 3-D modes observed in astrophysical plasmas (e.g. the solar atmosphere), laboratory set-ups must be designed to induce driven reconnection about an isolated magnetic null point. As such, we consider the limited range of fundamental resistive magnetohydrodynamic (MHD) and kinetic parameters of dynamic laboratory plasmas that are necessary to induce the torsional spine reconnection (TSR) mode characterized by a driven rotational slippage of field lines – a feature that has yet to be achieved in operational laboratory magnetic reconnection experiments. Leveraging existing reconnection models, we show that within a${\lesssim}1~\text{m}^{3}$apparatus, TSR can be achieved in dense plasma regimes (${\sim}10^{24}~\text{m}^{-3}$) in magnetic fields of${\sim}10^{-1}~\text{T}$. We find that MHD and kinetic parameters predict reconnection in thin${\lesssim}20~\unicode[STIX]{x03BC}\text{m}$current sheets on time scales of${\lesssim}10~\text{ns}$. While these plasma regimes may not explicitly replicate the plasma parameters of observed astrophysical phenomena, studying the dynamics of the TSR mode within achievable set-ups signifies an important step in understanding the fundamentals of driven 3-D magnetic reconnection and the self-organization of current sheets. Explicit control of this reconnection mode may have implications for understanding particle acceleration in astrophysical environments, and may even have practical applications to fields such as spacecraft propulsion.

scholarly journals Experimental Observation of Energetic Ions Accelerated by Three-dimensional Magnetic Reconnection in a Laboratory Plasma

2002 ◽  
Vol 577 (1) ◽  
pp. L63-L66 ◽  
Author(s):  
M. R. Brown ◽  
C. D. Cothran ◽  
M. Landreman ◽  
D. Schlossberg ◽  
W. H. Matthaeus
Keyword(s):  
Magnetic Reconnection ◽  
Experimental Observation ◽  
Three Dimensional ◽  
Laboratory Plasma ◽  
Energetic Ions

scholarly journals A magnetic reconnection model for hot explosions in the cool atmosphere of the Sun

2021 ◽  
Author(s):  
Lei Ni
Keyword(s):  
Magnetic Reconnection ◽  
Current Sheet ◽  
Large Temperature ◽  
Formation Mechanisms ◽  
Line Profiles ◽  
Turbulent Structures ◽  
Plasma Parameters ◽  
Magnetic Diffusivity ◽  
Reconnection Region ◽  
Initial Plasma

<p>UV bursts and Ellerman bombs are transient brightenings observed in the low solar atmospheres of emerging flux regions. Observations have discovered the cospatial and cotemporal EBs and UV bursts, and their formation mechanisms are still not clear. The multi-thermal components with a large temperature span in these events challenge our understanding of magnetic reconnection and heating mechanisms in the low solar atmosphere. We have studied magnetic reconnection between the emerging and background magnetic fields. The initial plasma parameters are based on the C7 atmosphere model. After the current sheet with dense photosphere plasma is emerged to <span tabindex="0" role="presentation" data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML"><mn>0.5</mn></math>'><span><span><span>0.5</span></span></span></span> Mm above the solar surface, plasmoid instability appears. The plasmoids collide and coalesce with each other, which makes the plasmas with different densities and temperatures mixed up in the turbulent reconnection region. Therefore, the hot plasmas corresponding to the UV emissions and colder plasmas corresponding to the emissions from other wavelenghts can move together and occur at about the same height. In the meantime, the hot turbulent structures basically concentrate above <span tabindex="0" role="presentation" data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML"><mn>0.4</mn></math>'><span><span><span>0.4</span></span></span></span> Mm, whereas the cool plasmas extend to much lower heights to the bottom of the current sheet. These phenomena are consistent with the observations of Chen et al. 2019, ApJL. The synthesized Si IV line profiles are similar to the observed one in UV bursts, the enhanced wing of the line profiles can extend to about <span tabindex="0" role="presentation" data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML"><mn>100</mn></math>'><span><span><span>100</span></span></span></span> km s<span tabindex="0" role="presentation" data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi></mi><mrow class="MJX-TeXAtom-ORD"><mo>−</mo><mn>1</mn></mrow></msup></math>'><span><span><span><span></span><span><span><span>−</span><span>1</span></span></span></span></span></span></span>. The differences are significant among the numerical results with different resolutions, which indicate that the realistic magnetic diffusivity is crucial to reveal the fine structures and realistic plasmas heating in these reconnection events. Our results also show that the reconnection heating contributed by ambipolar diffusion in the low chromosphere around the temperature minimum region is not efficient.</p>

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