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Proposal ID Kankelborg_35

Date of Proposal



Montana State University

Charles Kankelborg
Department of Physics
Montana State University
Bozeman, MT 59717-0350


406-994-6183 (ask for Dana)


X-ray bright points are believed to arise from the
reconnection of magnetic fields between two small features of opposite
polarity. Recent theoretical work has begun to elucidate the geometry
and kinematics of reconnection in three dimensions (Gorbochev and
Somov 1988; Longcope 1996a). These new three-dimensional theories have
been applied to the reconnection in X-ray bright points by Priest,
Parnell and Golub (1995) and by Longcope (1999b). In particular,
Longcope arrived at quantitative theoretical predictions for X-ray
bright points from four magnetic parameters: bipolar separation, flux,
orientation and the overlying (global) magnetic field strength. From
these properties the model yields the X-ray luminosity, based on the
rate of irreversible magnetic energy loss, and also yields an angle
between the X-ray loop and the magnetic bipole axis (Kankelborg et al.
We propose to study the process of reconnection in X-ray
bright points by using these theoretical predictions in conjunction
with a combination of EIT spectroheliograms and MDI high-resolution
magnetic field data. This study would require calibrated, daily
images from EIT in all three EUV bands, taken in rapid succession, plus a
consecutive pair of magnetograms from MDI's high-resolution FOV for
each daily EUV set. We would also require information on the
temperature response kernels of the telescopes in order to obtain
temperature and pressure information.
Data which is presently archived for both instruments should be
satisfactory for our purposes. Initially, we would hope to obtain a
dataset large enough to identify about 50 XBPs within the MDI high-
resolution field, resolved well enough to determine an orientation in
EUV. We estimate that three weeks of daily EUV images would be ample. If
our method of analysis shows promise based on this initial study, we would
like to obtain a larger sampling of data in order to improve our

Gorbachev and Somov, 1988, Sol. Phys. 117, 77.

Kankelborg, C.C., Walker, A.B.C. Jr., Hoover, R.B. and
Barbee, T.W., 1996, ApJ 466, 529.

Longcope, D.W., 1996a, "Topology and current ribbons: A model for
current, reconnection and flaring in a complex evolving corona", Sol.
Phys., to appear.

Longcope, D.W., 1996b, "Current sheets and reconnection in X-ray
bright points", AGU fall 1996.

Parnell, C.E., Priest, E.R. and Golub, L., 1994,
Sol. Phys. 151, 57.

Jim Lemen


Bright Points


Observations of magnetic reconnection in X-ray bright points

update added on 1998/03/04 at 15:58:05
Progress as of March, 1998

Effort so far has concentrated on developing the means for data
selection, reduction, and analysis. Software has been written for
coregistration and display of EIT and MDI images, cataloguing
of regions of interest, EUV background subtraction, analysis of
EUV morphology, and interpretation of the magnetogram in the
region of interest as a superposition of discreet magnetic
charges. All of this runs as an integrated package of widget
applications under IDL.

A first results poster, 'A Survey of X-ray Bright Points With
Application to a Reconnection Model' by Kankelborg, C. C.,
Longcope, D. W., and Pevtsov, A. A. will be presented at
the SPD/AGU joint meeting in May.

The scope of this effort has broadened a bit with the submission
of a GI proposal under the title "Topology and reconnection in a
survey of X-ray bright points", with Dana Longcope as PI and
Co-I's Charles Kankelborg and Alex Pevtsov. If the GI proposal is
funded, then an undergraduate student will be employed to search
the data for XBPs and to help with the analysis.

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