This project will investigate the possibility that a new approach to deriving a linear theory of the tearing mode instability in space plasmas can be successfully developed. Such a linear theory would then form the basis of a full non-linear theory of magnetic reconnection in a collisonless plasma. Previous analytical work on the linear tearing mode relied on using an asymptotic approach to make the equations tractable. However, fullly kinetic, particle simulations have indicated that the asymptotic approach breakes down in most realistic geometries. The purpose of this exploratory resarch is threefold: 1) Determine why the asymptotic appoach breaks down and develop a new approach using an exact linear Vlasov solver to determine the conditions where a direct transition from linear theory to non-linear turbulence occurs; 2) Determine whether or not the formation of secondary tearing island formation is due to a linear instability; 3) Examine the controversial question of whether linear mode properties have a significant influence on the resulting reconnection rate in large systems.
This is a project that has the potential to transform the way magnetic reconnection is treated in plasma theory and simulations. It could affect our understanding of phenomena on the sun, in the solar wind, in planetary magnetospheres and in astrophysical plasmas.
Earth is embedded in the Sun's extended atmosphere. As a result, the Earth and its technological systems are exposed to the hazards of magnetic storms on the Sun. The earth's magnetic dipole field protects us for the most part from such solar storms but this shielding is not perfect. A mechanism called magnetic reconnection enables the hot plasma from the Sun penetrate the Earth's protective shield, causing what is referred to as space weather. A strong solar storm can knock out satellites, disable high-voltage transformers, and cripple communications worldwide. It is projected that a solar storm of the magnitude of the 1859 Solar Superstorm would cause over $2 trillion in damage today. Thus there is an ugent need to develop accurate forecasts of space weather. Our work was focused on understanding the details of the magnetic reconnection process which is the mechanism leading to space weather effects on Earth. We had a novel idea that we wanted to explore further but given that the idea was contrary to conventional wisdom, it was difficult to get it funded. However, thanks for NSF's special program called EAGER that provides seed funding to explore innovative ideas, we were able to test our idea. The results surprised even us. We were able to address several outstanding issues related to magnetic reconnection. Our results were reported in two prestigous journals in plasma physics with a third publication in preparation.