Preferential acceleration of heavy ions in magnetic reconnection: Hybrid-kinetic simulations with electron inertia

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F24%3A00587667" target="_blank" >RIV/67985815:_____/24:00587667 - isvavai.cz</a>

Result on the web

<a href="https://hdl.handle.net/11104/0354792" target="_blank" >https://hdl.handle.net/11104/0354792</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202348573" target="_blank" >10.1051/0004-6361/202348573</a>

Result language

angličtina

Original language name

Preferential acceleration of heavy ions in magnetic reconnection: Hybrid-kinetic simulations with electron inertia

Original language description

Context. Solar energetic particles (SEPs) in the energy range 10 s KeV nucleon(-1)-100s MeV nucleon(-1) originate from the Sun. Their high flux near Earth may damage the space-borne electronics and generate secondary radiation that is harmful for life on Earth. Thus, understanding their energization on the Sun is important for space weather prediction. Impulsive (or He-3-rich) SEP events are associated with the acceleration of charge particles in solar flares by magnetic reconnection and related processes. The preferential acceleration of heavy ions and the extraordinary abundance enhancement of He-3 in the impulsive SEP events are not understood yet. Aims. In this paper we study the acceleration of heavy ions and its consequences for their abundance enhancements by magnetic reconnection, an established acceleration source for impulsive SEP events in which heavy-ion enhancement is observed Methods. We employed a two-dimensional hybrid-kinetic plasma model (kinetic ions and inertial electron fluid) to simulate magnetic reconnection. All the ion species are treated self-consistently in our simulations. Results. We find that heavy ions are preferentially accelerated to energies many times higher than their initial thermal energies by a variety of acceleration mechanisms operating in reconnection. The most efficient acceleration takes place in the flux pileup regions of magnetic reconnection. Heavy ions with sufficiently low values of charge-to-mass ratio (Q/M) can be accelerated by pickup mechanism in outflow regions even before any magnetic flux is piled up. The energy spectra of heavy ions develop a shoulder-like region, a nonthermal feature, as a result of the acceleration. The spectral index of the power-law fit to the shoulder region of the spectra varies approximately as (Q/M)(-0.64). The abundance enhancement factor, defined as the number of particles above a threshold energy normalized to the total number of particles, scales as (Q/M)(-alpha), where alpha increases with the energy threshold. We discuss our simulation results in the light of the SEP observations.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

<a href="/en/project/GC20-09922J" target="_blank" >GC20-09922J: Understanding modern radioastronomical observations via advanced astrophysical plasma simulations</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

686

Issue of the periodical within the volume

June

Country of publishing house

FR - FRANCE

Number of pages

9

Pages from-to

A28

UT code for WoS article

001231909000008

EID of the result in the Scopus database

2-s2.0-85194916546