Ripples in the pond of magnetic field reconnection

Nearly all of the seen matter within the Universe consists of charged particles or plasmas which can develop magnetic discipline reconnection (MR) on the locations the place the magnetic discipline route displays abrupt change. Via the MR the magnetic discipline power might successfully be transferred into the kinetic and thermal energies of plasmas, leading to many explosive plasma phenomena occurring on the Solar, planetary and pulsar magnetospheres, and even blackholes.

The interface or magnetopause between the photo voltaic wind and Earth’s magnetosphere (at about 70,000 km from the Earth) is among the most definitely websites in our photo voltaic system for the incidence of MR between interplanetary and Earth’s magnetic fields. The Earth’s magnetopause can be readily accessible for in-situ observations by spacecraft which can’t be carried out on the Solar and in different astronomical environments.

Magnetic reconnection might create cracks on the magnetopause boundary to stop the conducting magnetosphere from completely shielding the Earth’s house environments from photo voltaic wind. Within the core areas of MR the magnetic field with completely different instructions intersect, forming an X line. The identification of MR signatures in house environments has lengthy been an observational and theoretical problem resulting from the truth that the places of X traces can’t be predetermined and the spacecraft can solely view restricted parts of the buildings. The NASA Magnetospheric Multiscale (MMS) spacecraft consisting of 4 satellites 15 km aside and launched in 2015 is a state-of-the-art mission geared toward learning the multiscale physics of MR. 

Mirror waves with ripples like plasma and magnetic fields have been broadly noticed within the photo voltaic system that are the product of mirror instability occurring within the circumstances of huge temperature anisotropy. Particularly, when the temperature perpendicular to the magnetic discipline far exceeds the parallel temperature, the plasma might simply develop the mirror instability. Such anisotropic temperature traits are clearly evidenced by the MMS observations which have contributed to the findings of small scale mirror waves within the solar wind not seen in prior spacecraft missions.

Lately a analysis crew led by Professor Lin-Ni Hau of Nationwide Central College (Taiwan) have utilized the NASA MMS spacecraft information together with the theoretical models to disclose for the primary time the general geometry of magnetic reconnection (MR) with the presence of an X line throughout the spatial area of 2000 km x 2000 km. Inside 15-30 seconds of traversing throughout the Earth’s magnetopause, all 4 MMS spacecraft with exceptionally excessive temporal decision of 0.15 seconds have caught, for the primary time, the signatures of mirror waves surrounding the X line.

The 2 MR occasions are situated at 70,000 km and 150,000 km from the Earth, respectively, and exhibit frequent options of plasma and magnetic discipline ripples within the pond of MR with the spacecraft paths lower than 30 km from the X traces. The coexistence of MR and mirror waves are in assist of the sooner theoretical prediction of combined MR and mirror instability which can yield extra drastic processes of power conversion and plasma acceleration. The brand new discovery printed within the October subject of The Astrophysical Journal Letters (ApJL) by Hau et al. might have make clear the doable mechanism for the explosive magnetic reconnection phenomena occurring in house, photo voltaic and astronomical plasma environments.

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Nationwide Central College