HIGH-ENERGY PARTICLE-ACCELERATION DURING THE IMPLOSION DRIVEN BY 3-DIMENSIONAL X-TYPE CURRENT LOOP COALESCENCE IN SOLAR-FLARES

We present a model for high-energy solar flares to explain prompt proton and electron acceleration within 1 s to relativistic energies. The three-dimensional X-type current loop coalescence, where two crossed flux tubes interact in one point, is a fundamentally new process as compared to the one- and two-dimensional cases studied earlier. It is shown that the strong implosion can be driven by the magnetic pinch in the region where two current loops interact. The strong inductive electric field can be excited during the implosion. We investigated a test particle orbit under the electromagnetic fields derived from the MHD equations. It is also shown that both protons and electrons can be promptly (within less than 1 s) accelerated to ∼ 100 GeV and ∼ 100 MeV, respectively. We accentuate the fact that a well-developed high-energy flare has three phases of particle acceleration. The present acceleration mechanism can explain the first phase acceleration leading to relativistic energies within less than one second for both electrons and protons.