Analysis of Magnetic Reconnection Sequence: from 2d to 3d
Abstract
Magnetic reconnection, which governs explosive energy release in solar flares, is 3-dimensional by nature. One major challenge in the field has always been to find a useful quantitative description of observations that can relate to theoretic models of magnetic reconnection. In this study, we analyze the temporal and spatial evolution of UV ribbons of an X2.0 flare observed on 2004 November 7 to infer 3D evolution of magnetic reconnection in the corona. First, our analysis reveals macroscopically two distinctive stages of magnetic reconnection (e.g. Moore et al. 2001), namely parallel elongation and perpendicular expansion of flare ribbons with respect to the polarity inversion line (PIL). Elongation of flare ribbons along the PIL during the first stage proceeds at apparent maximum speeds comparable with the Alfven speed in the active region chromosphere, and the apparent perpendicular expansion speed is a fraction of the local Alfven speed. The two stages are also marked by a clear division in reconnection rate and energy release rate. Furthermore, we employ a new method, the reconnection sequence analysis, to determine the connectivity and reconnection flux during the flare between a dozen magnetic sources defined from partitioning the photospheric magnetogram. The method can pick up pairs of magnetic cells that are reconnecting in a sequential manner. The observationally derived reconnection sequence and cell-wise reconnection fluxes are compared with computations by a topological model of magnetic reconnection, yielding reasonable agreement. Such analysis produces physical quantities directly comparable with topological models, thus is promising to provide observational constraints to justify subsequent calculation of helicity transfer and energy release from the model.
This work is supported by NSF grants ATM-0603789 and ATM-0748428 to Montana State University.- Publication:
-
AAS/Solar Physics Division Meeting #40
- Pub Date:
- May 2009
- Bibcode:
- 2009SPD....40.2003Q