Numerical simulation of internal plasma dynamics of post-flare loops

CARLOS A. FERNÁNDEZ, ANDREA COSTA, SERGIO ELASKAR, GUADALUPE MARTÍNEZ, M. ROVIRA

Río de Janeiro, Brasil

Simposio; IAU Symposium 264 Solar and Stellar Variability - Impact on the Earth and Planets; 2009

International Astronomical Union

We integrate the MHD ideal equations of a slender flux tube to simulate the internal plasma dynamics of coronal post-flare loops. We study the onset and evolution of the internal plasma instability to compare with observations. The numerical approach uses a finite-volume Harten-Yee TVD scheme to integrate the 1D 1/2 MHD equations specially designed tocapture supersonic flow discontinuities. We show that high-speed downflow perturbations, usually interpreted as slow magnetoacoustic waves, could be better interpreted as slowmagnetoacoustic shock waves. A time-dependent forcing from the basis is needed to reproduce the reiteration of the event which resembles observational patterns –commonly known asquasi-periodic pulsations (QPPs)– which are related with large scale characteristic longitudes of coherence. This result reinforces the interpretation that the QPPs are response to thepulsational flaring activity.