Japan Geoscience Union Meeting 2016

Presentation information

International Session (Oral)

Symbol P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM06] Magnetospheric Multi-Scale (MMS) mission -- A new age of magnetospheric physics

Tue. May 24, 2016 9:00 AM - 10:30 AM 103 (1F)

Convener:*Seiji Zenitani(National Astronomical Observatory of Japan), Naritoshi Kitamura(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Yoshifumi Saito(Solar System Science Division, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Paul Cassak(West Virginia University), Li-Jen Chen(NASA Goddard Space Flight Center), Craig Pollock(NASA Goddard Space Flight Center), Chair:Mitsuo Oka(University of California Berkeley), Seiji Zenitani(National Astronomical Observatory of Japan)

9:00 AM - 9:15 AM

[PEM06-01] First Electron-Scale Measurements of Magnetic Reconnection in Space

★Invited papers

*James L Burch1, Roy B. Torbert1,2, Tai D. Phan3, Li-Jen Chen4, Thomas E Moore5, Robert E Ergun6, Jonathan P Eastwood7, Daniel J Gershman5, Matthew R Argall2, Shan Wang4, Michael Hesse5, Craig J Pollock15, Barbara L Giles5, Rumi Nakamura8, Barry H Mauk9, Stephen A Fuselier1, Christopher T Russell10, Robert J Strangeway10, Paul A Cassak11, James F Drake4, Michael A Shay12, Yuri Khotyaintsev13, Per-Arne Lindqvist14, Frederick D Wilder6, Mitsuo Oka3, John C Dorelli5, Jerry Goldstein1, Daniel N Baker6 (1.Southwest Research Institute, 2.University of New Hampshire, 3.University of California, Berkeley, 4.University of Maryland, 5.NASA, Goddard Space Flight Center, 6.University of Colorado LASP, 7.Imperial College London, 8.Space Research Institute, Austrian Academy of Sciences, 9.Johns Hopkins University Applied Physics Laboratory, 10.University of California, Los Angeles, 11.West Virginia University, 12.University of Delaware, 13.Swedish Institute of Space Physics, 14.Swedish Royal Institute of Technology, 15.Denali Scientific)

Keywords:Magnetic Reconnection, Solar-Wind Magnetosphere Interactions, Charged Particle Acceleration

Magnetic reconnection is a fundamental plasma physical process in which stored magnetic energy is explosively converted through the reconfiguration of a magnetic field into heat and kinetic energy of charged particles. Reconnection occurs in many astrophysical plasma environments as well as in laboratory plasma experiments and is responsible for solar flares and coronal mass ejections, x-ray flares in magnetars, magnetospheric storms and substorms, and sawtooth collapses in fusion devices. Although the effects of reconnection are easily observed, the electron-scale kinetic physics that allows plasmas to become demagnetized, with the resulting change in the topology of the magnetic field and the release of particle energy, has up to now eluded observation in both space and the laboratory. However, recent observations by NASA’s Magnetospheric Multiscale Mission (MMS), made with unprecedently high time resolution (100 times faster than previous missions for electrons and 30 times faster for ions), have provided the first detailed look at electron demagnetization and acceleration at sites along the sunward boundary of Earth’s magnetosphere where the interplanetary magnetic field encounters and reconnects with the terrestrial magnetic field. With these new measurements we have (1) observed the reduction of magnetic-field energy to near zero, (2) measured the reconnection electric field and the current that flows along it causing the dissipation of magnetic energy, and (3) identified the electron population that carries the current as a result of demagnetization and acceleration during their penetration of the reconnection dissipation region. The persistence of a characteristic crescent shape in the velocity-space distributions of these electrons suggests that the kinetic processes causing magnetic field line reconnection in this event were dominated by laminar electron physics rather than turbulence-induced dissipation.