Magnetic Reconnection and Intermittent Turbulence

Thursday, 18 December 2014: 11:14 AM
Kareem Osman1, William H Matthaeus2, Khurom Hussain Kiyani1, John T Gosling3, Sandra C Chapman4, Bogdan Hnat1, Antonella Greco5, Sergio Servidio6, Tai-Duc Phan7 and Yuri V Khotyaintsev8, (1)University of Warwick, Coventry, CV4, United Kingdom, (2)University of Delaware, Newark, DE, United States, (3)Univ Colorado, Boulder, CO, United States, (4)University of Warwick, Coventry, United Kingdom, (5)Dipartimento di Fisica, Universita della Calabria, Calabria, Italy, (6)Universita' della Calabria, Rende, Italy, (7)University of California Berkeley, Berkeley, CA, United States, (8)IRF Swedish Institute of Space Physics Uppsala, Uppsala, Sweden
The relationship between magnetic reconnection and plasma turbulence is investigated using in-situ measurements both in the solar wind and within a high-speed reconnection jet in the terrestrial magnetotail. In the solar wind, reconnection events and current sheets are found for the first time to be concentrated in intervals of intermittent turbulence: within the most non-Gaussian 1% of magnetic field fluctuations, 87-92% of reconnection exhausts and about 9% of current sheets are found. Also, the likelihood that an identified current sheet will also correspond to a reconnection exhaust increases dramatically as the least intermittent fluctuations are removed. Hence, the turbulent solar wind contains a hierarchy of intermittent magnetic field structures that are increasingly linked to current sheets, which in turn are progressively more likely to correspond to sites of magnetic reconnection. In a magnetotail reconnection jet, the work done by electromagnetic fields on the particles, J·E, is found for the first time to have a non-Gaussian heavy tailed probability density function. Furthermore, J·is non-uniform and concentrated in regions of high electric current density. This suggests magnetic energy is converted to kinetic energy within the reconnection jet in a manner that is intermittent, and could be analogous to fluid-like turbulent phenomenology where dissipation proceeds via coherent structures generated by an intermittent cascade. These results could have far reaching implications for space and astrophysical plasmas where turbulence and magnetic reconnection are ubiquitous.