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. |