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相关论文: Fast-to-Alfv\'en mode conversion mediated by Hall …

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The photospheric temperature minimum in the Sun and solar-like stars is very weakly ionized, with ionization fraction $f$ as low as $10^{-4}$. In galactic star forming regions, $f$ can be $10^{-10}$ or lower. Under these circumstances, the…

太阳与恒星天体物理 · 物理学 2015-12-02 Paul S. Cally , Elena Khomenko

A 2.5D numerical model of magnetoacoustic-Alfv\'en linear mode conversions in the partially ionised low solar atmosphere induced by the Hall effect is surveyed, varying magnetic field strength and inclination, and wave frequency and…

太阳与恒星天体物理 · 物理学 2021-08-06 Abbas Raboonik , Paul Cally

Alfv\'en waves may be generated via mode conversion from fast magneto-acoustic waves near their reflection level in the solar atmosphere, with implications both for coronal oscillations and for active region helio-seismology. In active…

太阳与恒星天体物理 · 物理学 2015-05-28 Paul S. Cally , Shelley C. Hansen

Complete asymptotic expansions are developed for slow, Alfv\'en and fast magnetohydrodynamic waves at the base of an isothermal three-dimensional (3D) plane stratified atmosphere. Together with existing convergent Frobenius series solutions…

太阳与恒星天体物理 · 物理学 2021-12-28 Paul S. Cally

We study the coupling of magneto-acoustic waves to Alven waves using 2.5D numerical simulations. In our experiment, a fast magnetoacoustic wave of a given frequency and wavenumber is generated below the surface. The magnetic field in the…

太阳与恒星天体物理 · 物理学 2015-05-20 Elena Khomenko , Paul Cally

An enhancement in high-frequency acoustic power is commonly observed in the solar photosphere and chromosphere surrounding magnetic active regions. We perform 3D linear forward wave modelling with a simple wavelet pulse acoustic source to…

太阳与恒星天体物理 · 物理学 2015-06-23 Carlos Rijs , Hamed Moradi , Damien Przybylski , Paul S. Cally

Magneto-hydrodynamic (MHD) Alfv\'en waves have been a focus of laboratory plasma physics and astrophysics for over half a century. Their unique nature makes them ideal energy transporters, and while the solar atmosphere provides…

The conversion of fast waves to the Alfven mode in a realistic sunspot atmosphere is studied through three-dimensional numerical simulations. An upward propagating fast acoustic wave is excited in the high-beta region of the model. The new…

太阳与恒星天体物理 · 物理学 2015-06-11 T. Felipe

Using linear Vlasov theory of plasma waves and quasi-linear theory of resonant wave-particle interaction, the dispersion relations and the electromagnetic field fluctuations of fast and Alfven waves are studied for a low-beta multi-ion…

太阳与恒星天体物理 · 物理学 2013-08-16 Ming Xiong , Xing Li

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,…

天体物理学 · 物理学 2009-11-13 P. S. Cally , M. Goossens

In this paper, we report our detailed analysis of the new strong-coupling regime between Alfv\'en and fast modes in Poynting-dominated plasma turbulence, reported in our previous work Takamoto & Lazarian (2016), which is an important effect…

高能天体物理现象 · 物理学 2017-10-18 Makoto Takamoto , Alexandre Lazarian

In the parts of the solar corona and solar wind that experience the fewest Coulomb collisions, the component proton, electron, and heavy ion populations are not in thermal equilibrium with one another. Observed differences in temperatures,…

太阳与恒星天体物理 · 物理学 2015-06-05 Steven R. Cranmer , Adriaan A. van Ballegooijen

We study the linear theory of magnetohydrodynamic (MHD) waves, namely the Alfv{\'e}n and the fast and slow magnetosonic modes in a rotating Hall-MHD plasma with the effects of the obliqueness of the external magnetic field and the Coriolis…

等离子体物理 · 物理学 2025-06-16 A. P. Misra , R. Dey , V. Krishan

Alfv\'en waves may be difficult to excite at the photosphere due to low ionization fraction and suffer near-total reflection at the transition region (TR). Yet they are ubiquitous in the corona and heliosphere. To overcome these…

太阳与恒星天体物理 · 物理学 2015-06-04 Shelley C. Hansen , Paul S. Cally

Context. Magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. In magnetic waveguides resonant absorption due to plasma inhomogeneity naturally transfers wave energy from large-scale motions to small-scale motions. In the…

太阳与恒星天体物理 · 物理学 2015-06-03 R. Soler , J. Andries , M. Goossens

This work is an extension of Kaghashvili [1999] where ion-cyclotron wave dissipation channel for Alfv\'en waves was discussed. While our earlier study dealt with the mode coupling in the commonly discussed sense, here we study changes in…

太阳与恒星天体物理 · 物理学 2014-02-10 Edisher Kh. Kaghashvili

Mode conversion in the region where the sound and Alfven speeds are equal is a complex process, which has been studied both analytically and numerically, and has been seen in observations. In order to further the understanding of this…

天体物理学 · 物理学 2008-08-04 A. M. Dee McDougall , Alan W. Hood

We use the exact solutions for magnetoacoustic waves in a two dimensional isothermal atmosphere with uniform inclined magnetic field to calculate the wave reflection, transmission, and conversion of slow and fast waves incident from above…

太阳与恒星天体物理 · 物理学 2016-01-27 Shelley Hansen , Paul Cally , Alina Donea

A ray-theoretic phase space description of linear waves in a two-fluid (charges and neutrals) magnetized plasma is used to calculate analytic decay rates and mode transmission and conversion coefficients between fast and slow waves in two…

太阳与恒星天体物理 · 物理学 2023-04-12 Paul S Cally , M. M. Gomez-Miguez

We have performed a 2.5 dimensional magnetohydrodynamic simulation that resolves the propagation and dissipation of Alfven waves in the solar atmosphere. Alfvenic fluctuations are introduced on the bottom boundary of the extremely large…

太阳与恒星天体物理 · 物理学 2015-06-18 Takuma Matsumoto , Takeru K. Suzuki
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