2D fully kinetic simulations of dayside magnetic
reconnection in the presence of cold ions and a moderate
guide field.

Mohammed Baraka, Olivier Le Contel, Alessandro Retino, Jérémy Dargent, Arnaud Beck, Sergio Toledo-Redondo, Giulia Cozzani, Stephen Fuselier, Thomas Chust, Soboh Alqeeq

► To cite this version:

Mohammed Baraka, Olivier Le Contel, Alessandro Retino, Jérémy Dargent, Arnaud Beck, et al.. 2D fully kinetic simulations of dayside magnetic reconnection in the presence of cold ions and a moderate guide field. European Geosciences Union General Assembly 2025 (EGU25), EGU, Apr 2025, Vienna (AUSTRIA), Austria. 10.5194/egusphere-egu25-18438 . hal-05338718

HAL Id: hal-05338718

https://hal.science/hal-05338718v1

Submitted on 31 Oct 2025

**HAL** is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
<figure><img src="image_2.png" /></figure>

2D fully kinetic simulations of dayside magnetic reconnection in the
presence of cold ions and a moderate guide field.

Mohammed Baraka<fnref n="1" />, **Olivier Le Contel**<fnref n="1" />, Alessandro Retino<fnref n="1" />, Jérémy Dargent<fnref n="1" />, Arnaud Beck<fnref n="2" />,
Sergio Toledo-Redondo<fnref n="3" />, Giulia Cozzani<fnref n="4" />, Stephen Fuselier<fnref n="5" />, Thomas Chust<fnref n="1" />, and Soboh Alqeeq<fnref n="1" />

The standard conditions considered for magnetic reconnection to occur are usually antiparallel
magnetic field configurations with a shear angle of 180°. Reconnection is often observed with an
additional out-of-plane component of the magnetic field (guide field). We performed two sets of
2D fully kinetic simulations using SMILEI code of asymmetric reconnection. The first set was
performed initially by Dargent et al., 2017 with and without cold ions. While the second set with
and without cold ions each conducted in the presence of a moderate guide field. The simulation
domain size is set to (x_max, y_max) = (320, 128) dᵢ, enabling us to study these effects in the electron
diffusion region (EDR) as well as the coupling across different scales, including ion diffusion region
(IDR), outflow jets, and extended separatrices far from diffusion region. When the density gradient
is combined with a guide field component at the magnetopause, it was suggested by Swisdak et
al., 2003 that the electron diamagnetic drift governs the motion of the X-line.

Our simulations reveal the development of an asymmetry in the reconnection plane as expected
and a motion of the X-line in the opposite direction of the electron diamagnetic drift. This finding
challenges the previously proposed explanation. We also report our progress in investigating the
impact of cold ions in reinforcing the electron dynamics and further investigate the impact of
adding a moderate guide field in their presence. These effects are expected to influence the
energization, energy partitioning across scales, and potentially the suppression of reconnection.
Fluid scales coupling with smaller ion scales aligns with the primary objective of the Plasma
Observatory (PO) mission which aims to study plasma energization and energy transport. Our
findings will contribute to the preparation of the PO mission and aim at improving its science
return.

<footnote n="1">¹CNRS, Laboratoire de physique des plasmas (LPP UMR7648), Paris, France (mohammed.baraka@lpp.polytechnique.fr)</footnote>

<footnote n="2">²Laboratoire Leprince-Ringuet, Palaiseau, France</footnote>

<footnote n="3">³Departamento Electromagnetismo y Electronica, Universidad de Murcia, Murcia, Spain</footnote>

<footnote n="4">⁴Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LCP2E), Orléans, France</footnote>

<footnote n="5">⁵Southwest Research Institute, San Antonio, TX, USA</footnote>