| Popis: |
We carry out a detailed analysis of the X3.5 solar flare that occurred on 2002 July 20, which is the strongest partially limb-occulted flare ever observed by the RHESSI satellite. The main results are: (1) during the main impulsive phase that lasts similar to 10 minutes, the motion of the thermal sources follows a U-shaped trajectory. Non-thermal sources move in a similar way, but in a series of larger zigzags. We further show that the non-thermal sources are actually leading the contraction motion. (2) During the main impulsive phase, X-ray sources at different energies continuously form a loop-like configuration, with the highest energy source (up to similar to 100 keV) and the lowest energy source (down to similar to 10 keV) being located at two ends. The entire loop-like configuration moves in a U-shaped trajectory, while keeping the order of descending energy from highest to lowest during motion. Two non-thermal hard Xray sources with different energies are spatially well separated in the distribution. The unusual complexities of the X-ray emissions in the tenuous solar corona challenge interpretations using bremsstrahlung in a simple magnetic configuration. |
