Investigating the Mechanism of the Acceleration of Cosmic Rays during Solar Flares Using the Electric Field in Current Sheets of the Solar Corona

Solar energetic particles are an integral part of the physical processes related with space weather. We present a review for the acceleration mechanisms related to the explosive phenomena (flares and/or coronal mass ejections, CMEs) inside the solar corona. For more than 40 years, the main two-dimensional cartoon representing our understanding of the explosive phenomena inside the solar corona remained almost unchanged. The acceleration mechanisms related to solar flares and CMEs also remained unchanged and were part of the same cartoon. In this review, we revise the standard cartoon and present evidence from recent global magnetohydrodynamic simulations that support the argument that explosive phenomena will lead to the spontaneous formation of current sheets in different parts of the erupting magnetic structure. The evolution of the large-scale current sheets and their fragmentation will lead to strong turbulence and turbulent reconnection during solar flares and turbulent shocks. In other words, the acceleration mechanism in flares and CME-driven shocks may be the same, and their difference will be the overall magnetic topology, the ambient plasma parameters, and the duration of the unstable driver. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

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Motion of Flare Footpoint Emission and Inferred Electric Field in Reconnecting Current Sheets

The Astrophysical Journal ◽

10.1086/324706 ◽

2002 ◽

Vol 565 (2) ◽

pp. 1335-1347 ◽

Cited By ~ 143

Author(s):

Jiong Qiu ◽

Jeongwoo Lee ◽

Dale E. Gary ◽

Haimin Wang

Keyword(s):

Electric Field ◽

Current Sheets

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Propagation of an MHD Shock in the Vicinity of a Magnetic Neutral Sheet

Symposium - International Astronomical Union ◽

10.1017/s0074180900067802 ◽

1980 ◽

Vol 91 ◽

pp. 323-326

Author(s):

D. J. Mullan ◽

R. S. Steinolfson

Keyword(s):

Magnetic Field ◽

Cosmic Rays ◽

Solar Corona ◽

Large Scale ◽

Field Structure ◽

Neutral Sheet ◽

Solar Cosmic Rays ◽

Magnetic Field Structure ◽

Large Scale Magnetic Field ◽

Highly Correlated

The acceleration of solar cosmic rays in association with certain solar flares is known to be highly correlated with the propagation of an MHD shock through the solar corona (Svestka, 1976). The spatial structure of the sources of solar cosmic rays will be determined by those regions of the corona which are accessible to the flare-induced shock. The regions to which the flare shock is permitted to propagate are determined by the large scale magnetic field structure in the corona. McIntosh (1972, 1979) has demonstrated that quiescent filaments form a single continuous feature (a “baseball stitch”) around the surface of the sun. It is known that helmet streamers overlie quiescent filaments (Pneuman, 1975), and these helmet streamers contain large magnetic neutral sheets which are oriented essentially radially. Hence the magnetic field structure in the low solar corona is characterized by a large-scale radial neutral sheet which weaves around the entire sun following the “baseball stitch”. There is therefore a high probability that as a shock propagates away from a flare, it will eventually encounter this large neutral sheet.

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Cause-and-effect relations between cosmic rays, electric field, aerosols and clouds

10.5194/egusphere-egu21-544 ◽

2021 ◽

Author(s):

Stavros Stathopoulos ◽

Stergios Misios ◽

Konstantinos Kourtidis

Keyword(s):

Cosmic Rays ◽

Electric Field ◽

Causal Effect ◽

Atmospheric Electricity ◽

Potential Gradient ◽

Galactic Cosmic Rays ◽

The European Union ◽

Development Education ◽

Cause And Effect ◽

Global Coordination

Here we examine the cause-and-effect relations between galactic cosmic rays, electric field, aerosols and clouds over a region of Atlantic Ocean, during a Forbush Decrease (FD) event on 07/12/2015, using Convergent Cross Mapping (CCM) method. For this purpose, we used FD data from the Neuron Monitor Database (NMDB), Potential Gradient data (PG) from Global Coordination of Atmospheric Electricity Measurements (GLOCAEM) and remote sensing data from MODIS/Aqua, namely Aerosol Optical Depth at 550nm (AOD), Cloud Fraction (CF), Cloud Optical Thickness (COT), Cloud Top Pressure (CTP), Cirrus Reflectance (CR) and Cloud Effective Radius-Liquid (CERL). A cause-and-effect relation was found between FD and AOD, CERL, CF and PG, over the region. On the other hand, no causal effect was found between FD and COT, CTP and CR. This research is funded in the context of the project "Cosmic and electric effects on aerosols and clouds&#8221; (MIS: 5049552) under the call for proposals &#8220;Support for researchers with emphasis on young researchers - Cycle B&#8221; (EDULL 103). The project is co-financed by Greece and the European Union (European Social Fund - ESF) by the Operational Programme Human Resources Development, Education and Lifelong Learning 2014-2020.

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NUMERICAL EXPERIMENTS ON FINE STRUCTURE WITHIN RECONNECTING CURRENT SHEETS IN SOLAR FLARES

The Astrophysical Journal ◽

10.1088/0004-637x/737/1/14 ◽

2011 ◽

Vol 737 (1) ◽

pp. 14 ◽

Cited By ~ 74

Author(s):

Chengcai Shen ◽

Jun Lin ◽

Nicholas A. Murphy

Keyword(s):

Fine Structure ◽

Solar Flares ◽

Numerical Experiments ◽

Current Sheets

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Solar Orbiter observations of solar wind current sheets and their deHoffman-Teller frames

10.5194/egusphere-egu21-10630 ◽

2021 ◽

Author(s):

Konrad Steinvall ◽

Yuri Khotyaintsev ◽

Giulia Cozzani ◽

Andris Vaivads ◽

Christopher Owen ◽

...

Keyword(s):

Solar Wind ◽

Electric Field ◽

Wind Velocity ◽

Solar Wind Velocity ◽

Field Measurements ◽

Velocity Measurements ◽

Current Sheets ◽

Spacecraft Orbit ◽

Electric Field Measurements ◽

Good Agreement

Solar wind current sheets have been extensively studied at 1 AU. The recent advent of Parker Solar Probe and Solar Orbiter (SolO) has enabled us to study these structures at a range of heliocentric distances.We present SolO observations of current sheets in the solar wind at heliocentric distances between 0.55 and 0.85 AU, some of which show signatures of ongoing magnetic reconnection. We develop a method to find the deHoffman-Teller frame which minimizes the Y-component (the component tangential to the spacecraft orbit) of the electric field. Using the electric field measurements from RPW and magnetic field measurements from MAG, we use our method to determine the deHoffman-Teller frame of solar wind current sheets. The same method can also be used on the Alfv&#233;nic turbulence and structures found in the solar wind to obtain a measure of the solar wind velocity.Our preliminary results show a good agreement between our modified deHoffmann-Teller analysis based on the single component E-field, and the conventional deHoffman-Teller analysis based on 3D plasma velocity measurements from PAS. This opens up the possibility to use the RPW and MAG data to obtain an estimate of the solar wind velocity when particle data is unavailable.

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MHD Aspects of Coronal Transients

Symposium - International Astronomical Union ◽

10.1017/s007418090006770x ◽

1980 ◽

Vol 91 ◽

pp. 263-277 ◽

Cited By ~ 1

Author(s):

U. Anzer

Keyword(s):

Solar Corona ◽

Time Scales ◽

White Light ◽

Solar Flares ◽

Great Length ◽

X Ray

If one defines coronal transients as events which occur in the solar corona on rapid time scales (≲ several hours) then one would have to include a large variety of solar phenomena: flares, sprays, erupting prominences, X-ray transients, white light transients, etc. Here we shall focus our attention on the latter two phenomena; solar flares have been discussed at great length in a recent Skylab workshop and IAU Colloqium No. 44 was devoted to the study of prominences. Coronal transients, in the narrower sense, were first seen with the instruments on board of Skylab, both in the optical and the X-ray part of the spectrum.

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Particle Orbits, Trapping, and Acceleration in a Filamentary Current Sheet Model

International Astronomical Union Colloquium ◽

10.1017/s0252921100078027 ◽

1994 ◽

Vol 142 ◽

pp. 719-728

Author(s):

Bernhard Kliem

Keyword(s):

Particle Acceleration ◽

Electric Field ◽

Test Particle ◽

Solar Flares ◽

Acceleration Of Particles ◽

Acceleration Process ◽

Two Dimensional ◽

Magnetic Island ◽

Particle Orbits ◽

Island Dynamics

AbstractTest particle orbits in the two-dimensional Fadeev equilibrium with a perpendicular electric field added are analyzed to show that impulsive bursty reconnection, which has been proposed as a model for fragmentary energy release in solar flares, may account also for particle acceleration to (near) relativistic energies within a fraction of a second. The convective electric field connected with magnetic island dynamics can play an important role in the acceleration process.Subject headings: acceleration of particles — MHD — plasmas — Sun: corona — Sun: flares

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