Speaker
Prof.
Hantao Ji
(Princeton University)
Description
Despite its disruptive influences on the large-scale structures of space
and solar
plasmas, the crucial topological changes and associated dissipation
during magnetic
reconnection take place only near an X-line within thin singular layers
on the electron
scales. While ion dissipation layers have been frequently detected, the
existence of
election layers near the X-line and the associated dissipation structures
and
mechanisms are still an open question, and will be a main subject of
the MMS mission.
In this presentation, we will revisit the significant discrepancy on the
thickness of the
electron dissipation layer measured in the MRX experiment [1,2] and in
the PIC
simulation [3,4]. Although the long wave-length, electromagnetic
lower-hybrid drift
instabilities has been ruled out as a candidate to explain the
discrepancy [5], other
two candidates have emerged as possible explanations: (a) 3D flux-
rope-like magnetic
structures [6] and (b) micro-instabilities at frequencies higher than the
lower-hybrid
frequency including Debye-scale electrostatic turbulence [7].
Discussions will also
include additional results from experimental evidence of electron
heating through non-
classical mechanisms near the X-line [8], as well as the relevant space
observations.
We will also present the construction status of the upcoming FLARE
device [9] which is
designed to access new regimes of magnetic reconnection involving
multiple X-lines.
The prospective research topics on FLARE will be discussed in relation
to the dynamics
of the Earth’s magnetosphere.
[1] Y. Ren et al., Phys. Rev. Lett. 101, 085003 (2008)
[2] H. Ji et al., Geophys. Res. Lett. 35, L13106 (2008)
[3] S. Dorfman et al., Phys. Plasmas 15, 102107 (2008)
[4] V. Roytershteyn et al., Phys. Plasmas 17, 055706 (2010)
[5] V. Roytershteyn et al., Phys. Plasmas 20, 055705 (2013)
[6] S. Dorfman et al., Geophys. Res. Lett. 40, 233 (2013); N. Jain, et
al., Phys.
Plasmas 20, 112101 (2013)
[7] J. Jara-Almonte et al., Phys. Plasmas 21, 032114 (2014)
[8] J. Yoo et al., Phys. Rev. Lett. 110, 215007 (2013); Phys. Rev. Lett.
113, 095002
(2014)
[9] H. Ji and W. Daughton, Phys. Plasmas 18, 111207 (2011)
Primary author
Prof.
Hantao Ji
(Princeton University)
