Mode conversion and damping of MHD waves in stratified viscous solar atmosphere

被引:1
作者
Kumar, Nagendra [1 ]
Kumar, Anil [2 ]
机构
[1] Mahanand Miss Harijan Coll, Dept Math, Ghaziabad 201001, Uttar Pradesh, India
[2] Maharaja Agarsen Inst Technol, Dept Math, Delhi 110086, India
关键词
Waves; Sun: atmosphere; Sun: magnetic fields; MAGNETOGRAVITY WAVES; RESONANT ABSORPTION; ALFVEN WAVES; OSCILLATIONS; REFLECTION;
D O I
10.1007/s10509-020-03785-7
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We study the mode conversion and damping of MHD waves in a gravitationally stratified low-beta to high-beta isothermal atmosphere of the Sun permeated by a uniform vertical magnetic field. We solve the MHD equations by MacCormack method to examine the effect of viscosity on amplitudes of physical quantities such as velocity, mass density, gas pressure and magnetic field before and after the beta approximate to 1 layer. It is found that mode conversion occurs at the point z approximate to-1.8 in beta approximate to 1 layer and viscosity does not influence the mode conversion phenomenon. In the presence of viscosity, the amplitudes of vertical and horizontal velocity components, horizontal and vertical magnetic field components, gas pressure and mass density decrease and decay of amplitude is stronger for higher values of viscosity. In the low beta plasma, damping length decreases with the increase in viscosity but remains almost unchanged in the high beta plasma. When the driving frequency increases, conversion from slow to fast mode decreases.
引用
收藏
页数:14
相关论文
共 22 条
[1]   Waves in the magnetized solar atmosphere.: II.: Waves from localized sources in magnetic flux concentrations [J].
Bogdan, TJ ;
Hansteen, MCV ;
McMurry, A ;
Rosenthal, CS ;
Johnson, M ;
Petty-Powell, S ;
Zita, EJ ;
Stein, RF ;
McIntosh, SW ;
Nordlund, Å .
ASTROPHYSICAL JOURNAL, 2003, 599 (01) :626-660
[2]  
Braginskii S. I., 1965, REV PLASMA PHYS, V1, P205
[3]   What to look for in the seismology of solar active regions [J].
Cally, P. S. .
ASTRONOMISCHE NACHRICHTEN, 2007, 328 (3-4) :286-291
[4]   Simulation of f- and p-mode interactions with a stratified magnetic field concentration [J].
Cally, PS ;
Bogdan, TJ .
ASTROPHYSICAL JOURNAL, 1997, 486 (01) :L67-L70
[5]   Note on an exact solution for magnetoatmospheric waves [J].
Cally, PS .
ASTROPHYSICAL JOURNAL, 2001, 548 (01) :473-481
[6]   Dispersion relations, rays and ray splitting in magnetohelioseismology [J].
Cally, PS .
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 2006, 364 (1839) :333-349
[7]   Numerical modelling of MHD waves in the solar chromosphere [J].
Carlsson, M ;
Bogdan, TJ .
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 2006, 364 (1839) :395-404
[8]   The damping of slow MHD waves in solar coronal magnetic fields - III. The effect of mode coupling [J].
De Moortel, I ;
Hood, AW ;
Gerrard, CL ;
Brooks, CJ .
ASTRONOMY & ASTROPHYSICS, 2004, 425 (02) :741-752
[9]   Resonantly damped oscillations of longitudinally stratified coronal loops [J].
Dymova, M. V. ;
Ruderman, M. S. .
ASTRONOMY & ASTROPHYSICS, 2006, 457 (03) :1059-1070
[10]  
ERDELYI R, 1995, ASTRON ASTROPHYS, V294, P575