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Alfv\'en waves play three related roles in the impulsive phase of a solar flare: they transport energy from a generator region to an acceleration region; they map the cross-field potential (associated with the driven energy release) from…

Solar and Stellar Astrophysics · Physics 2015-06-15 D. B. Melrose , M. S. Wheatland

The efficacy of fast/slow MHD mode conversion in the surface layers of sunspots has been demonstrated over recent years using a number of modelling techniques, including ray theory, perturbation theory, differential eigensystem analysis,…

Astrophysics · Physics 2009-11-13 P. S. Cally , M. Goossens

Motivated by recent Parker Solar Probe (PSP) observations of "switchbacks" (abrupt, large-amplitude reversals in the radial magnetic field, which exhibit Alfv\'enic correlations) we examine the dynamics of large-amplitude Alfv\'en waves in…

Alfv\'en waves are responsible for the transfer of magnetic energy in the magnetized plasma. They are involved in heating solar atmosphere and driving solar wind through various nonlinear processes. Since the magnetic field configurations…

Solar and Stellar Astrophysics · Physics 2020-08-04 Takahito Sakaue , Kazunari Shibata

Two populations of twisted magnetic field tubes, or flux ropes (hereafter, FRs), are detected by in situ measurements in the solar wind. While small FRs are crossed by the observing spacecraft within few hours, with a radius typically less…

Solar and Stellar Astrophysics · Physics 2015-06-22 M. Janvier , P. Demoulin , S. Dasso

We could infer a secular decreasing trend in the poloidal to toroidal solar magnetic flux amplification factor ( Af) using geomagnetic observations ( classic and IHV corrected aa indices) during the sunspot cycles 9-23. A similar decreasing…

General Physics · Physics 2010-12-23 T. E. Girish , G. Gopkumar

This paper re-evaluates the relationship between the observed sunward electron cutoff energy and the depth of the Sun's global electrostatic potential. It investigates whether taking into account the effects of local traps formed by…

Solar and Stellar Astrophysics · Physics 2026-02-19 Zoltan Nemeth

We perform numerical simulations of impulsively generated magnetic swirls in an isolated flux tube which is rooted in the solar photosphere. These swirls are triggered by an initial pulse in a horizontal component of the velocity. The…

Solar and Stellar Astrophysics · Physics 2017-12-13 K. Murawski , P. Kayshap , A. K. Srivastava , D. J. Pascoe , P. Jelínek , B. Kuźma , V. Fedun

The Solar Probe Plus (SPP) spacecraft will explore the near-Sun environment, reaching heliocentric distances less than $10 R_{\odot}$. Near Earth, spacecraft measurements of fluctuating velocities and magnetic fields taken in the time…

Forecasting models of the solar wind often rely on simple parameterizations of the magnetic field that ignore the effects of the full magnetic field geometry. In this paper, we present the results of two solar wind prediction models that…

Solar and Stellar Astrophysics · Physics 2015-06-19 Lauren N. Woolsey , Steven R. Cranmer

We use the magnetic butterfly diagram to determine the speed of the magnetic flux transport on the solar surface towards the poles. The manifestation of the flux transport is clearly visible as elongated structures extended from the sunspot…

Astrophysics · Physics 2009-11-13 M. Svanda , A. G. Kosovichev , J. Zhao

Waves connect all the layers of the Sun, from its interior to the upper atmosphere. It is becoming clear now the important role of magnetic field on the wave propagation. Magnetic field modifies propagation speed of waves, thus affecting…

Astrophysics · Physics 2015-05-13 Elena Khomenko

The long-term evolution of the Sun's rotation period cannot be directly observed, and is instead inferred from trends in the measured rotation periods of other Sun-like stars. Assuming the Sun spins-down as it ages, following rotation rate…

The k-filtering technique and wave polarization analysis are applied to Cluster magnetic field data to study plasma turbulence at the scale of the ion gyroradius in the fast solar wind. Waves are found propagating in directions nearly…

Solar and Stellar Astrophysics · Physics 2015-06-15 Owen W. Roberts , Xing Li , Bo Li

We derive formulae connecting the frequency variations in the spectrum of solar oscillations to the dynamical quantities that are expected to change over the solar activity cycle. This is done for both centroids and the asymmetric part of…

Astrophysics · Physics 2009-11-10 W. A. Dziembowski , P. R. Goode

We investigate the anisotropy of Alfv\'enic turbulence in the inertial range of slow solar wind and in both driven and decaying reduced magnetohydrodynamic simulations. A direct comparison is made by measuring the anisotropic second-order…

Space Physics · Physics 2012-08-20 C. H. K. Chen , A. Mallet , T. A. Yousef , A. A. Schekochihin , T. S. Horbury

A major discovery of Parker Solar Probe (PSP) was the presence of large numbers of localized increases in the radial solar wind speed and associated sharp deflections of the magnetic field - switchbacks (SB). A possible generation mechanism…

This study investigates the gravitational waves (GWs) generated by the emergence of magnetic flux tubes in the solar convection zone. We focus on the upward buoyancy of magnetic flux tubes, which leads to significant magnetic activity and…

Solar and Stellar Astrophysics · Physics 2025-10-17 Siqi Guan , Shangbin Yang , Xiao Guo

Magnetic reconnection in current sheets converts magnetic energy into particle energy. The process may play an important role in the acceleration and heating of the solar wind close to the Sun. Observations from Parker Solar Probe provide a…

Magnetic waves are a relevant component in the dynamics of the solar atmosphere. Their significance has increased because of their potential as a remote diagnostic tool and their presumed contribution to plasma heating processes. We discuss…

Solar and Stellar Astrophysics · Physics 2023-07-19 I. Arregui
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