Proposal for SOI/MDI observation and data access:
Magnetic Topology and X-ray Loops
Dana Longcope and Loren Acton
Montana State University,
Physics Department, Bozeman, MT 59717-0350
The solar corona, when viewed in the X-ray, consists of many
individual bright loops which trace out specific magnetic field lines
(Rosner, Tucker and Vaiana 1978). It has been speculated the
magnetic reconnection is responsible for much coronal activity,
including the brightening of coronal loops. If this is the case, then
reconnection must occur on specific isolated field lines. Recent
theoretical work has begun to explore the relationship between
magnetic topology and reconnection in three dimensions(Gorbachev and
Somov 1988; Longcope 1996a). These theoretical studies have
identified specific magnetic field lines, called separators, along which
current sheets should form and reconnection can take place. It
remains to explore the possible relationships between these
theoretically significant field lines and the bright loops observed in
the X-ray.
We propose to explore this relationship by comparing Yohkoh
soft X-ray telescope (SXT) images with magnetic field models. Of
particular interest are quiescent active regions of modest complexity,
such as the older decaying region that passed the central meridian
around September 24, 1996. The magnetic topology can be modeled from
an MDI magnetogram, enabling the locations of separator field lines to
be calculated. These can then be compared in detail to Yohkoh SXT
images. This can be done with existing data of that particular
region, so no new observations will be necessary. We are eager to
proceed with this work as soon as possible. If this proposal is
approved please let us know how to access and interpret the MDI
magnetograms. We will be doing this work in IDL.
Gorbachev and Somov, 1988, Sol. Phys. 117, 77.
Longcope, D.W., 1996a, "Topology and current ribbons: A model for
current, reconnection and flaring in a complex evolving corona", Sol.
Phys., to appear.
No additional text was submitted for this proposal.