Satellites encounter magnetic reconnection in Earth's magnetotail

Research published in the respected journal Science presents observations made by NASA's four Magnetospheric Multiscale (MMS) satellites in the Earth's magnetotail. Two scientists from the Swedish Institute of Space Physics (IRF) in Uppsala are co-authors of the article. The lead author is from the University of New Hampshire in USA.

Magnetic reconnection is an energy conversion process important in many astrophysical contexts including the Earth's magnetosphere, where the process releases the energy powering the auroras. The article presents the first encounter of a reconnection site by the MMS spacecraft in the magnetotail, one of the few regions where the process can be investigated by satellites in-situ.

The unprecedented electron-scale plasma measurements revealed super-Alfvenic electron jets reaching 15,000 km/s, electron meandering motion and acceleration by the electric field. Despite the presence of turbulence near the reconnection site, the well-structured multiple layers of electron populations indicate that the key electron dynamics appear to be largely laminar.

The magnetotail reconnection electron diffusion region differs from that on the dayside as it involves symmetric conditions on both sides of the reconnecting current sheet. MMS determined the aspect ratio of the diffusion region (0.1-0.2), which is consistent with predictions for fast reconnection.

The MMS observations of electron dynamics in the diffusion region match predictions made by one class of theories and models - nearly laminar ones that assume the effects of turbulence and associated fluctuations on the electron dynamics are small.

Electrons can be accelerated up to three successive times by the reconnection electric field, possibly as a consequence of longer confinement in the symmetric magnetic structure. Taken together with MMS observations at the magnetopause, these results provide confirmation that reconnection is an efficient mechanism for the release of magnetic energy, for both geomagnetic substorms and auroral phenomena.

"The magnetotail plasma sheet is one of the hottest places in our solar system, with plasma temperatures reaching 100 million degrees," says Yuri Khotyaintsev of the Swedish Institute of Space Physics. "Reconnection is one of the key processes involved in heating the plasma. The new MMS measurements help us to understand how the plasma particles and in particular electrons are accelerated during reconnection."

"Electron-Scale Dynamics of the Diffusion Region During Symmetric Magnetic Reconnection in Space," R. B. Torbert et al., 2018 Nov. 15, Science

Related Links
Space Plasma Physics at IRF
Earth Observation News - Suppiliers, Technology and Application

Tweet

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only

SpaceDaily Contributor
$5 Billed Once

credit card or paypal

OpenForests launches the forest project platform explorer.land
Krefeld, Germany (SPX) Nov 12, 2018
OpenForests (https://openforests.com), an innovative German forest consulting and tech company, just released the explorer.land platform. The interactive map-based platform is designed to present forest and landscape projects and tell their stories while connecting like-minded organizations and stakeholders from around the world. "We believe that explorer.land will cause a substantial paradigm shift in the way sustainable forest and landscape projects are presented to the world," says Dr. Patrick ... read more