An interpretation of the phase background based on observed plasma jets

¹ I.N.A.F., Osservatorio Astronomico di Capodimonte, Via Moiarello 16, 80131 Napoli, Italy
² Department of Physics University of Rome, P.le A. Moro 2, 00185 Rome, Italy
³ Institute of Geophysics, Astrophysics and Meteorology of the University of Graz, Universitaetsplatz 5, 8010 Graz, Austria
⁴ I.N.A.F., Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34131 Trieste, Italy
⁵ Kanzelhhe Solar Observatory, 9521 Treffen, Austria

Corresponding author: P. F. Moretti, moretti@na.astro.it

Received: 13 November 2001
Accepted: 4 September 2002

Abstract

The presence of a solar background in the phase difference between the intensity and velocity () p-mode oscillation signals recently has been interpreted in terms of downflows due to convection (Skartlien & Rast [CITE]) or due to chromospheric explosive events (Moretti et al. [CITE]a). In support of the latter, we present I and V characteristics of impulsive brightenings observed in the NaI D lines, show that these reproduce the frequency dependence of the modulation background, and show that explanations invoking more frequently occurring phenomena such as seismic events are not likely in low-l modulation data.