The fractal reconnection scenario: energy cascade induced by magnetic reconnection.

In Webseminar by admin

Speaker: Fulvia Pucci,Bochum universityRuhr

Abstract: Magnetic reconnection is considered to be the energy source underlying flares and outbursts, from Pulsar wind nebulae, to primordial galaxy clusters energy release. Jets of active galactic nuclei, energy conversion in GRBs and accretion disks, are now believed to be powered by magnetic energy dissipation. The idea that the mechanisms behind the explosive events mentioned previously and explosive events in the solar corona might be the same, stems from the similarity between power-law spectra inferred for these astrophysical environments and solar flares.

When magnetic reconnection is at play, primary reconnection sites most often evolve due to current sheet collapse, island merging and secondary modes growth. These dynamics inspired Shibata & Tanuma (2001) to develop the fractal tearing reconnection scenario: the current sheet collapses originating secondary tearing reconnection sites; these thin themselves, transferring energy down to smaller scales, through a self-similar process.
In this talk I will discuss the results on self-similar current sheet collapse which suggested introducing the revised fractal reconnection scenario in the context of resistive MHD reconnection. The results from this work prove that understanding the onset of magnetic reconnection is fundamental to provide a universal model for magnetic reconnection and its nonlinear outcome.