CORONAL MANIFESTATIONS OF OSCILLATIONS: A NUMERICAL MODEL A.S. Andreev

We have studied the nonlinear response of the solar atmosphere to a single event of excitation of oscillations, located just beneath the photosphere. Some of the energy of the excitation goes into the internal p modes; the remainder results in transient oscillations in the chromosphere and corona. The most remarkable manifestation of the transient is formation of quasi-periodic shock waves in the upper chromosphere and corona, the so called `nonlinear wave-wake effect'. We present results of nonlinear one-dimensional simulations of the process, and suggest cooperative studies of the phenomena using observations from MDI and SOHO coronal instruments. Keywords: solar atmosphere, corona, oscillations, excitation, acoustic events, nonlinear wave-wake effect, SOHO 1. INTRODUCTION High-resolution observations of the Sun show that excitation of solar oscillations preferentially occurs in localized acoustic events near the surface (Brown et al., 1992; Restaino et al., 1993). There is also ev..