Abstract


  STOCHASTIC TRANSIENTS AS A SOURCE OF QUASI-PERIODIC PROCESS IN SOLAR AND STELLAR ATMOSPHERE

  D. Yuan, University of Central Lancashire, DYuan2@uclan.ac.uk
  R. Walsh, University of Central Lancashire,
  J. Su, National Astronomical Observatory of China,

Transient processes are observed at multiple heights of the solar and stellar atmospheres, e.g. convections, granulations, spicules, surges, nanoflare (reconnections). These transients have finite lifetime and recur with non-constant interval. Their finite lifetime, recurrence time, strength are not constant but follows a certain distribution. In this talk, we present a model of stochastic driver consisting of a series of finite lifetime transients. A transient is assumed to have a Gaussian profile in time domain for simplicity. The amplitude (strength) is random and has an uniform distribution, while centroid (occurring time) and width (lifetime) are also random numbers and have a normally distribution. Using the statistical measures of spicular activities and other transients, surges, mottles, we reproduced typical spectrum observed at coronal holes and sunspots. We also model how a stochastic driver propagates in stratified atmosphere with photosphere, chromosphere, transition region and corona temperatures. This model could indeed explain a number of quasi-periodic processes in the solar and stellar atmospheres.