Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
MAGNETOHYDROSTATIC MODEL OF A BALD-PATCH FLARE G. AULANIER1, P. DMOULIN1, B. SCHMIEDER1, C. FANG2 and Y. H. TANG2
 

Summary: MAGNETOHYDROSTATIC MODEL OF A BALD-PATCH FLARE
G. AULANIER1, P. DÉMOULIN1, B. SCHMIEDER1, C. FANG2 and Y. H. TANG2
Observatoire de Paris, DASOP, F-92195 Meudon, France;
Department of Astronomy, Nanjing University, Nanjing 210093, China
(Received 23 April 1998; accepted 30 July 1998)
Abstract. On 18 May, 1994, a subflare was observed in AR 7722 in X-rays by Yohkoh/SXT and in
H at National Astronomical Observatory of Japan. The associated brightenings are due to small-
scale magnetic energy release, triggered by parasitic fluxes emerging and moving at the edge of
leading sunspots. Using the magnetohydrostatic equations derived by Low (1992), we model the
magnetic field configuration by extrapolation of the Kitt Peak photospheric field, taking into account
the effects of pressure and gravity. H flare kernels are shown to be located at computed separatrices
associated with field lines which are tangent to the photosphere, namely `bald patches' (BPs). This
is evidence that BPs can be involved in flares, and that current sheets can be dissipated in low levels
of the solar atmosphere. The presence of dense plasma which is supported against gravity in the
magnetic dips above BPs is correlated to dark elongated features observed in H. Mass flows in
these flat fibrils are discussed in the context of energy release in the BP separatrices. The effect of
the plasma on the computed magnetic configuration is shown to be of secondary importance with
respect to the topology of the field.
1. Introduction
Several observational studies at different wavelengths show that flares, and even

  

Source: Aulanier, Guillaume - Observatoire de Paris

 

Collections: Physics