May 1-3

Log in

Abstract Details

files Add files

status:file name:submitted:by:
approveddrake_reconn.pdf2017-05-15 08:50:14James Drake


Author: James F Drake
Requested Type: Pre-Selected Invited
Submitted: 2017-03-16 10:55:04


Contact Info:
University of Maryland
IREAP Paint Branch Drive
College Park, MD   20742

Abstract Text:
Magnetic reconnection converts energy into high-speed flows, thermal
and energetic particles in a broad range of systems both in the
heliosphere and the broader universe. The most detailed measurements
are within the heliosphere, which therefore acts as an effective
laboratory for many issues related to reconnection. While the
mechanisms for fast reconnection are now fairly well understood, the
energy conversion mechanisms and the partitioning between species are
active topics. In solar flares the energy released is roughly equally
partitioned between the thermal particles and the energetic
components. In the magnetosphere and the laboratory thermal ions carry
the bulk of the released energy and the scaling of the temperature
increments of both species with the available free energy per particle
$m_ic_{Aup}^2$ has recently been established. Models and simulations
are advancing the physics in both relativistic and non-relativistic
reconnection. Most of the energy conversion takes place in the exhaust
where newly reconnected field lines release their tension and during
the merger of magnetic islands. The three basic mechanisms for energy
conversions are Fermi reflection, parallel electric fields and
betatron acceleration. The former two mechanisms are typically the
most important with Fermi reflection dominating the energy gain of the
most energetic particles in both electron-ion and pair plasma. The
production of particles with energy greatly exceeding $m_ic_{Aup}^2$
requires the interaction with multiple magnetic islands. The dominant
energy gain is parallel to the local magnetic field and as a
consequence significant anisotropy develops, which is likely to impact
synchrotron signatures in astrophysical systems. Why the powerlaw
distributions that are typically seen in nature are produced remains
an open question.