ar075.canfield04 Posted: 27-Nov-94 Updated: 02-Aug-95, 03-Feb-96 Events specified: jets in AR 7260
Collaborators: UH: Canfield, Reardon, Leka; NAOJ: Shibata, Yokoyama, Shimojo Question: What is the nature of magnetic reconnection in the surges and jets observed in this region? Motivation: X-ray jets are one of the major discoveries of Yohkoh. In AR7260, numerous jets were observed by SXT and simultaneous H-alpha surges were observed by Mees Solar Observatory. The MSO observations include MCCD H-alpha imaging spectra, which give both H-alpha images and vector velocity maps with 20-second resolution. They also include Stokes and IVM magnetograms, which tell how the photospheric magnetic field evolves. About 10 events are observed by both MSO and SXT on 19 August, 1992, which form the observational basis for this study. Analysis: We will first study the dynamics and magnetic morphology of these events. We are testing a cartoon model, strongly related to the mhd simulations by Yokoyama et al. Satellite sunspots are moving outward from this spot, in the manner of moving magetic features but much larger. The surges and jets are associated with these features, which seem to play the same role as flux emergence for the jet process that takes place in coronal holes. Once we have finished the morphological analysis, we plan to work on energetics, with the goal of determining as much as possible about the relative energetics and dynamics of X-ray and H-alpha emitting gas.
Update 3-Feb-96
Please note that the TeamBB proposal ar075: H-alpha Surges and X-ray Jets in AR 7260 (August 1992) (Canfield) has been completed. The reference is:
Canfield, R. C., Reardon, K. P., Leka, K. D., Shibata, K., Yokoyama, T., and Shimojo, M., ``H$\alpha$ Surges and X-ray Jets in AR 7260'' {\it Astrophysical Journal}, in press, (1996)
Update 02-Aug-95
We gave a talk at Makuhari in May and finished the manuscript in July, and will submit it after editing is completed. In the manuscript we discuss nine events, observed simultaneously as jets in X-rays and surges in \Ha, which we attribute to the reconnection of moving magnetic bipoles with surrounding coronal fields. The X-ray jets share many features with those discovered by Yohkoh in active regions, emerging flux regions, and X-ray bright points; in particular, they originate near one end of a pair of small flaring loops. The H-alpha surges are adjacent to the X-ray jets. At the bases of these surges we observe both blueshifts (initially) and redshifts (1--2 minutes later). All the observed surges spin in a sense consistent with the relaxation of the observed stored twist of the region. Newly discovered phenomena include footpoint convergence and moving-blueshift features in these loops.
We developed a model of the role of magnetic reconnection in these events. This model explains the temporal and spatial relationship between the jets and surges, the role of the moving bipoles, the flaring X-ray loops and their converging H-alpha footpoints, the H-alpha moving-blueshift features, the spin of the surges, and the temporal development of the H-alpha redshifts and blueshifts.