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Related papers: Ponderomotive Acceleration in Coronal Loops

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The origin of the slow solar wind is not well understood, unlike the fast solar wind which originates from coronal holes. In-situ elemental abundances of the slow solar wind suggest that it originates from initially closed field lines that…

Solar and Stellar Astrophysics · Physics 2025-02-28 Alexandros Koukras , Daniel W. Savin , Michael Hahn

From a turbulent history, the study of abundances of elements in solar energetic particles (SEPs) has grown into an extensive field that probes the solar corona and the physical processes of SEP acceleration and transport. Underlying SEPs…

Solar and Stellar Astrophysics · Physics 2019-11-22 Donald V Reames

We investigate the propagation of Alfv\'en waves in the solar chromosphere, distinguishing between upward and downward propagating waves. We find clear evidence for the reflection of waves in the chromosphere and differences in propagation…

We investigate numerically the time evolution of velocity and magnetic field fluctuations in a coronal loop, focusing on the dynamics due to both phase mixing and turbulent cascade. The intensity, doppler velocity and non-thermal broadening…

The composition of the solar corona differs from that of the photosphere, with the plasma thought to fractionate in the solar chromosphere according to the First Ionisation Potential (FIP) of the different elements. This produces a FIP…

The Coronal Multi-channel Polarimeter (CoMP) has previously demonstrated the presence of Doppler velocity fluctuations in the solar corona. The observed fluctuations are thought to be transverse waves, i.e. highly incompressible motions…

Solar and Stellar Astrophysics · Physics 2016-09-21 R. J. Morton , S. Tomczyk , R. F. Pinto

Context: Acceleration in coronal mass ejection driven shocks is currently considered the primary source of large solar energetic particle events. Aims: The solar wind, which feeds shock-accelerated particles, includes numerous ion…

Solar and Stellar Astrophysics · Physics 2013-03-19 Markus Battarbee , Timo Laitinen , Rami Vainio

Plasma composition in the solar atmosphere differs between the photosphere and corona, producing an observable difference in elemental abundance known as the FIP effect. The FIP effect is characterised by the ratio of low to high FIP…

Solar and Stellar Astrophysics · Physics 2026-03-06 Kristena D. Spruksta , David M. Long , Andy S. H. To

This work consists of two parts: the first devoted to the study of the heating of the magnetically confined Solar Corona, and the second to the acceleration of the Slow Solar Wind. Direct 3D reduced MHD simulations are presented. They model…

Solar and Stellar Astrophysics · Physics 2010-01-13 A. F. Rappazzo

Solar atmospheric elemental abundances are now known to vary both in space and time. Dynamic modeling of these changes is therefore necessary to improve the accuracy of radiative hydrodynamic simulations. Recent studies have shown that…

Solar and Stellar Astrophysics · Physics 2026-02-13 David H. Brooks , Jeffrey W. Reep , Andy S. H. To , Luke Fushimi Benavitz , Lucas A. Tarr

The primary focus of this paper is on the particle acceleration mechanism in solar coronal three-dimensional reconnection null-point regions. Starting from a potential field extrapolation of a Solar and Heliospheric Observatory (SOHO)…

Solar and Stellar Astrophysics · Physics 2013-07-09 G. Baumann , T. Haugbølle , Å. Nordlund

It is extremely difficult to simulate the details of coronal heating and also make meaningful predictions of the emitted radiation. Thus, testing realistic models with observations is a major challenge. Observational signatures of coronal…

Solar and Stellar Astrophysics · Physics 2022-11-02 James A. Klimchuk , Kalman J. Knizhnik , Vadim M. Uritsky

The element abundances in the solar corona and solar wind are often different from those of the solar photosphere, typically with a relative enrichment of elements with low first ionization potential (FIP effect). Here we study the spatial…

Solar and Stellar Astrophysics · Physics 2023-02-22 Paola Testa , Juan Martinez-Sykora , Bart De Pontieu

The Parker hypothesis (Parker (1972)) assumes that heating of coronal loops occurs due to reconnection, induced when photospheric motions braid field lines to the point of current sheet formation. In this contribution we address the…

Solar and Stellar Astrophysics · Physics 2016-06-15 M. L. Ritchie , A. L. Wilmot-Smith , G. Hornig

Acceleration and transport of solar energetic particles (SEPs) causes their abundances, measured at constant velocity, to be enhanced or suppressed as a function of each ion's magnetic rigidity, and hence its atomic mass-to-charge ratio…

Solar and Stellar Astrophysics · Physics 2024-02-19 Donald V. Reames

We show that the coronal heating and the fast solar wind acceleration in the coronal holes are natural consequence of the footpoint fluctuations of the magnetic fields at the photosphere, by performing one-dimensional magnetohydrodynamical…

Astrophysics · Physics 2009-11-11 Takeru K. Suzuki , Shu-ichiro Inutsuka

Nonthermal loop-top sources in solar flares are the most prominent observational signature that suggests energy release and particle acceleration in the solar corona. Although several scenarios for particle acceleration have been proposed,…

Solar and Stellar Astrophysics · Physics 2020-01-08 Xiangliang Kong , Fan Guo , Chengcai Shen , Bin Chen , Yao Chen , Sophie Musset , Lindsay Glesener , Peera Pongkitiwanichakul , Joe Giacalone

Coronal mass ejections (CMEs) are thought to drive collisionless shocks in the solar corona, which in turn have been shown capable of accelerating solar energetic particles (SEPs) in minutes. It has been notoriously difficult to extract…

Solar and Stellar Astrophysics · Physics 2015-06-19 Kamen A. Kozarev , John C. Raymond , Vasili V. Lobzin , Michael Hammer

We study the relationship between implosive motions in a solar flare, and the energy redistribution in the form of oscillatory structures and particle acceleration. The flare SOL2012-03-09T03:53 (M6.4) shows clear evidence for an…

Solar and Stellar Astrophysics · Physics 2015-06-17 P. J. A. Simões , L. Fletcher , H. S. Hudson , A. J. B. Russell

An outstanding problem in heliospheric physics is understanding the acceleration of solar energetic particles (SEP) in coronal mass ejections (CMEs) and flares. A fundamental question is whether the acceleration occurs in interplanetary…

Solar and Stellar Astrophysics · Physics 2019-10-09 Kamen Kozarev , Maher A. Dayeh , Ashraf Farahat