The Influence of the Temperature Profile on the Magnetohydrodynamic Modes of a Prominence-Corona System

Abstract

view Abstract Citations (22) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Influence of the Temperature Profile on the Magnetohydrodynamic Modes of a Prominence-Corona System Oliver, R. ; Ballester, J. L. Abstract To explain the observational evidence gathered during recent years about periodic oscillations in quiescent solar prominences the modes of oscillation of some theoretical models for solar prominences have been studied. The main drawback of these models is the lack of a realistic temperature profile for the prominence- corona system, which should be obtained from the coupling between magnetostatics and energetics once the physical properties of the prominence and the prominence-corona transition region (PCTR) are known. However, this seems to be far from our present possibilities since there is a lack of knowledge about the physical processes occurring in both. To make further progress in the study of MHD waves in prominences, we have adopted an "ad hoc" temperature profile that can be adjusted to give different runs of the temperature, from prominence to coronal values. This profile allows us to modify the thickness of the PCTR while modifying the steepness of the temperature variation within it. Also, by including this profile in the model proposed by Poland & Anzer, we are able to construct an equilibrium model for the prominence-corona system and to study the linear, adiabatic MHD waves of such configuration. Among the results obtained we highlight that the presence of a PCTR does not eliminate the subdivision of modes into hybrid, external, and internal and that its existence is linked to the presence of two temperature plateaus. A change in the thickness of the PCTR produces a modification of the mode frequency and also affects the horizontal velocity component of internal modes by diminishing its amplitude in the prominence region. For a thin PCTR, because of the velocity amplitude inside the prominence, the modes likely to be detected in prominence oscillations are the internal and hybrid ones, although as a consequence of the effect already pointed out, the existence of a thick PCTR could make difficult or even impossible the detection of internal modes. In summary, our results point out the importance of the PCTR to the oscillations of quiescent solar prominences and to the identification of modes through the amplitudes of the eigenfunctions in the prominence. This indicates the strong need for accurate knowledge of the physical properties of this region, in order to be able to make accurate theoretical predictions about the amplitudes and frequencies of oscillations in quiescent prominences. Probably, that knowledge can be obtained in the near future by means of the UV instruments of the SOHO spacecraft. Publication: The Astrophysical Journal Pub Date: January 1996 DOI: 10.1086/176661 Bibcode: 1996ApJ...456..393O Keywords: MAGNETOHYDRODYNAMICS: MHD; SUN: PROMINENCES; SUN: MAGNETIC FIELDS; SUN: CORONA full text sources ADS |