Slow and sausage loop mode excitation due to local and global spontaneous perturbations
Abstract
Aims: We analyse the capability of different types of perturbations associated with usual environment energy fluctuations of the solar corona to excite slow and sausage modes in solar flaring loops.
Methods: We performed numerical simulations of magnetohydrodynamic ideal equations with a consideration of straight plasma magnetic tubes subject to local and global energy depositions.
Results: We find that local loop energy depositions of typical microflares [∼(1027 - 1030) erg] are prone to driving slow shock waves that induce slow-mode patterns. The slow-mode features are obtained for every tested local energy deposition inside the loop. Meanwhile, in order to obtain an observable sausage mode pattern, a global perturbation that is capable of instantaneously modifying the internal loop temperature is required; specifically, the characteristic conductive heating time must be much smaller than the radiative cooling one. Experiments carried out by varying the parameter β demonstrate that the excitation of sausage modes does not significantly depend on the value of this parameter but, rather, depends on the global or local character of the energy source.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- December 2020
- DOI:
- 10.1051/0004-6361/202039023
- arXiv:
- arXiv:2011.00140
- Bibcode:
- 2020A&A...644A.106C
- Keywords:
-
- Sun: oscillations;
- Sun: corona;
- magnetohydrodynamics (MHD);
- shock waves;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 9 pages, 14 figures