The Role of Nonlinear Alfven Waves in Shear Formation during Solar Magnetic Flux Emergence

2001 ◽  
Vol 547 (1) ◽  
pp. 503-519 ◽  
Author(s):  
Ward Manchester IV
Keyword(s):  
Magnetic Flux ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Flux Emergence

scholarly journals Concurrent effect of Alfvén waves and planar magnetic structure on geomagnetic storms

2019 ◽  
Vol 490 (3) ◽  
pp. 3440-3447 ◽  
Author(s):  
Zubair I Shaikh ◽  
Anil Raghav ◽  
Geeta Vichare ◽  
Ankush Bhaskar ◽  
Wageesh Mishra ◽  
...  
Keyword(s):  
Magnetic Structure ◽  
Geomagnetic Storms ◽  
Recovery Phase ◽  
Alfven Waves ◽  
Magnetic Clouds ◽  
Alfvén Waves ◽  
Fast Recovery ◽  
Interplanetary Coronal Mass Ejection ◽  
Mass Ejection

ABSTRACT Generally, interplanetary coronal mass ejection (ICME) triggers intense and strong geomagnetic storms. It has been established that the ICME sheath-moulded planar magnetic structure enhances the amplitude of the storms. Alfvén waves embedded in ICME magnetic clouds or high solar streams including corotating interacting regions (CIRs) in turn extend the recovery phase of the storm. Here, we investigate a geomagnetic storm with a very complex temporal profile with multiple decreasing and recovery phases. We examine the role of planar magnetic structure (PMS) and Alfvén waves in the various phases of the storm. We find that fast decrease and fast recovery phases are evident during transit of PMS regions, whereas a slight decrease or recovery is found during the transit of regions embedded with Alfvénic fluctuations.

scholarly journals Numerical simulations of the lower solar atmosphere heating by two-fluid nonlinear Alfvén waves

2020 ◽  
Vol 639 ◽  
pp. A45
Author(s):  
B. Kuźma ◽  
D. Wójcik ◽  
K. Murawski ◽  
D. Yuan ◽  
S. Poedts
Keyword(s):  
Magnetic Flux ◽  
Numerical Simulations ◽  
Solar Atmosphere ◽  
Flux Tube ◽  
Alfven Waves ◽  
Alfven Wave ◽  
Magnetic Flux Tube ◽  
Alfvén Waves ◽  
Two Fluid ◽  
Lower Solar Atmosphere

Context. We present new insight into the long-standing problem of plasma heating in the lower solar atmosphere in terms of collisional dissipation caused by two-fluid Alfvén waves. Aims. Using numerical simulations, we study Alfvén wave propagation and dissipation in a magnetic flux tube and their heating effect. Methods. We set up 2.5-dimensional numerical simulations with a semi-empirical model of a stratified solar atmosphere and a force-free magnetic field mimicking a magnetic flux tube. We consider a partially ionized plasma consisting of ion + electron and neutral fluids, which are coupled by ion-neutral collisions. Results. We find that Alfvén waves, which are directly generated by a monochromatic driver at the bottom of the photosphere, experience strong damping. Low-amplitude waves do not thermalize sufficient wave energy to heat the solar atmospheric plasma. However, Alfvén waves with amplitudes greater than 0.1 km s−1 drive through ponderomotive force magneto-acoustic waves in higher atmospheric layers. These waves are damped by ion-neutral collisions, and the thermal energy released in this process leads to heating of the upper photosphere and the chromosphere. Conclusions. We infer that, as a result of ion-neutral collisions, the energy carried initially by Alfvén waves is thermalized in the upper photosphere and the chromosphere, and the corresponding heating rate is large enough to compensate radiative and thermal-conduction energy losses therein.

Role of trapped and circulating particles in inducing current drive and radial electric field by Alfvén waves in tokamaks

2002 ◽  
Vol 67 (5) ◽  
pp. 301-308 ◽  
Author(s):  
V. S. TSYPIN ◽  
R. M. O. GALVÃO ◽  
I. C. NASCIMENTO ◽  
M. TENDLER ◽  
J. H. F. SEVERO ◽  
...  
Keyword(s):  
Electric Field ◽  
Radial Electric Field ◽  
Alfven Waves ◽  
Current Drive ◽  
Alfvén Waves ◽  
Trapped Particles ◽  
Transport Barriers

Absorption by trapped particles is supposed to seriously hinder current drive by Alfvén waves. However, it is shown in this paper that the same effect is rather beneficial for the emergence of the radial electric field induced by these waves, which is important for creating and maintaining transport barriers in tokamaks.

scholarly journals Numerical Simulations of Torsional Alfvén Waves in Axisymmetric Solar Magnetic Flux Tubes

Solar Physics ◽  
2017 ◽  
Vol 292 (2) ◽  
Author(s):  
D. Wójcik ◽  
K. Murawski ◽  
Z. E. Musielak ◽  
P. Konkol ◽  
A. Mignone
Keyword(s):  
Magnetic Flux ◽  
Numerical Simulations ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Flux Tubes ◽  
Magnetic Flux Tubes

scholarly journals Thermal electron anisotropy driven by kinetic Alfven waves in the Earth's magnetotail

2020 ◽  
Author(s):  
Alexander Lukin ◽  
Anton Artemyev ◽  
Evgeny Panov ◽  
Rumi Nakamura ◽  
Anatoly Petrukovich ◽  
...  
Keyword(s):  
Electric Fields ◽  
Electromagnetic Waves ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Plasma Flows ◽  
Thermal Electron ◽  
Electron Population ◽  
Electron Field ◽  
Kinetic Alfvén Waves

Abstract. Thermal and subthermal electron populations in the Earth's magnetotail are usually characterized by pronounced field-aligned anisotropy that contributes to generation of strong electric currents within the magnetotail current sheet. Formation of this anisotropy requires electron field-aligned acceleration, and thus likely involves field-aligned electric fields. Such fields can be carried by various electromagnetic waves generated by fast plasma flows interacting with ambient magnetotail plasma. In this paper we consider one of the most intense observed wave emissions, kinetic Alfven waves, that often accompany fast plasma flows in the magnetotail. Using two tail seasons (2017, 2018) of MMS observations we have collected statistics of 80 fast plasma flows (or bursty bulk flows) events with distinctive enhancement of intensity of broadband electromagnetic waves (kinetic Alfven waves). We show correlation the intensity of electric fields of kinetic Alfven waves and characteristics of electron anisotropy distributions: the parallel electron anisotropy increases with magnitude of the wave parallel electric field. Also the energy range of this electron anisotropic population is well within the expected acceleration range for assumed kinetic Alfven waves. Our results indicate an important role of KAWs in production of thermal field-aligned electron population typically observed in the Earth's magnetotail.

scholarly journals Intermittent chaos driven by nonlinear Alfvén waves

2004 ◽  
Vol 11 (5/6) ◽  
pp. 691-700 ◽  
Author(s):  
E. L. Rempel ◽  
A. C.-L. Chian ◽  
A. J. Preto ◽  
S. Stephany
Keyword(s):  
Dynamical Systems ◽  
Periodic Orbits ◽  
Systems Approach ◽  
Alfven Waves ◽  
Space Plasmas ◽  
Alfvén Waves ◽  
Unstable Periodic Orbits ◽  
Phase Dynamics ◽  
Intermittent Chaos

Abstract. We investigate the relevance of chaotic saddles and unstable periodic orbits at the onset of intermittent chaos in the phase dynamics of nonlinear Alfvén waves by using the Kuramoto-Sivashinsky (KS) equation as a model for phase dynamics. We focus on the role of nonattracting chaotic solutions of the KS equation, known as chaotic saddles, in the transition from weak chaos to strong chaos via an interior crisis and show how two of these unstable chaotic saddles can interact to produce the plasma intermittency observed in the strongly chaotic regimes. The dynamical systems approach discussed in this work can lead to a better understanding of the mechanisms responsible for the phenomena of intermittency in space plasmas.

Role of 3d-dispersive Alfven waves in coronal heating

2014 ◽  
Vol 351 (1) ◽  
pp. 75-80 ◽  
Author(s):  
R. P. Sharma ◽  
N. Yadav ◽  
N. Pathak
Keyword(s):  
Alfven Waves ◽  
Coronal Heating ◽  
Alfvén Waves
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