Magnetic Topology in 1998 November 5 Two-Ribbon Flare as Inferred from Ground-based Observations and Linear Force-free Field Modeling

We analyzed the three-dimensional structure of the linear force-free magnetic field. A longitudinal magnetogram of Active Region NOAA 8375 has been used as the photospheric boundary condition. The 1998 November 5 2B/M8.4 two-ribbon flare can be explained in the framework of quadrupolar reconnection theory: the interaction of two closed magnetic loops that have a small spatial angle. The energy derived from soft X-ray telescope (SXT)/Yohkoh data (3-6 × 1030 ergs) is 1 order of magnitude higher than the lower limit of flare energy predicted by Melrose's model. The latter estimation was made using the linear force-free extrapolation. It was suggested that, taking into account the nonlinear character of the observed magnetic field, we can increase the lower limit of the magnetic energy stored in the studied magnetic configuration. The revealed magnetic configuration allows us to understand the observed location and evolution of the flare ribbons and the additional energy released during the gradual phase of the flare, as well. Besides, reconnection of closed magnetic loops can logically explain the connection between a two-ribbon flare and a giant X-ray postflare arch, which usually is observed after the flare onset. We emphasize that unlike the Kopp and Pneuman configuration, the model discussed here does not necessarily require destabilization and opening of the magnetic field.

[1]  M. Aschwanden,et al.  Quadrupolar Magnetic Reconnection in Solar Flares. I. Three-dimensional Geometry Inferred from Yohkoh Observations , 1999 .

[2]  V. Carbone,et al.  Sign-Singularity of the Current Helicity in Solar Active Regions , 1998 .

[3]  B. Schmieder,et al.  POST-FLARE LOOPS OF 26 JUNE 1992 – IV. Formation and Expansion of Hot and Cool Loops , 1997 .

[4]  T. Sakurai,et al.  Magnetic Field Configuration in Impulsive Solar Flares Inferred from Coaligned Microwave/X-Ray Images , 1997 .

[5]  D. Melrose.  A Solar Flare Model Based on Magnetic Reconnection between Current-carrying Loops , 1997 .

[6]  Y. Hanaoka.  DOUBLE-LOOP CONFIGURATION OF SOLAR FLARES , 1997 .

[7]  D. Longcope.  Topology and current ribbons: A model for current, reconnection and flaring in a complex, evolving corona , 1996 .

[8]  H. Hudson,et al.  Large-scale active coronal phenomena in Yohkoh SXT images , 1996 .

[9]  Loukas Vlahos,et al.  Coronal Heating by Nanoflares and the Variability of the Occurrence Frequency in Solar Flares , 1996 .

[10]  V. Abramenko,et al.  Modeling of a linear force-free magnetic field in a bounded domain , 1996 .

[11]  L. Golub,et al.  Differential Magnetic Field Shear in an Active Region , 1996 .

[12]  Y. Hanaoka.  Flares and plasma flow caused by interacting coronal loops , 1996 .

[13]  H. Hudson,et al.  The 1991 October 24 flare: A challenge for standard models , 1995 .

[14]  B. Schmieder,et al.  Relation between cool and hot post-flare loops of 26 June 1992 derived from optical and X-ray (SXT-Yohkoh) observations , 1995 .

[15]  P. Démoulin,et al.  Interpretation of multiwavelength observations of November 5, 1980 solar flares by the magnetic topology of AR 2766 , 1994 .

[16]  Z. B. Korobova,et al.  Observational study of the ‘post’-flare loops on June 4, 1991 , 1993 .

[17]  M. Karlický,et al.  An analysis of Skylab X-ray pictures of a giant coronal arch , 1993 .

[18]  B. Schmieder,et al.  Structure and dynamics of cool flare loops , 1992 .

[19]  G. Poletto,et al.  The birth of giant post-flare arches , 1992 .

[20]  E. Priest,et al.  Magnetic flipping: Reconnection in three dimensions without null points , 1992 .

[21]  T. Forbes.  Field opening and reconnection , 1992 .

[22]  B. Schmieder.  “Post” flare loops , 1992 .

[23]  E. Lu,et al.  Avalanches and the Distribution of Solar Flares , 1991 .

[24]  R. Kopp,et al.  Formation and cooling of the giant HXIS arches of November 6–7, 1980 , 1990 .

[25]  B. Somov,et al.  Photospheric vortex flows as a cause for two-ribbon flares: A topological model , 1988 .

[26]  B. Vršnak,et al.  Evidence for interacting loop process in a phase of the May 16, 1981 flare , 1987 .

[27]  F. Tang.  Flare morphologies and coronal field configurations , 1985 .

[28]  Z. Svestka.  Revivals of a coronal arch , 1984 .

[29]  R. Loughhead,et al.  High-resolution photography of the solar chromosphere , 1984 .

[30]  George M. Simnett,et al.  Observations of a post-flare radio burst in X-rays , 1982 .

[31]  Eric Ronald Priest,et al.  An emerging flux model for the solar flare phenomenon , 1977 .

[32]  R. Kopp,et al.  Magnetic reconnection in the corona and the loop prominence phenomenon , 1976 .

[33]  T. Hirayama.  Theoretical model of flares and prominences , 1974 .

[34]  J. Roy.  The magnetic configuration of the November 18, 1968 loop prominence system , 1972 .

[35]  P. Sturrock.  A Model of Solar Flares , 1968 .