Magnetospheric Multiscale analysis of intense field‐aligned Poynting flux near the Earth's plasma sheet boundary. Issue 14 (18th July 2017)

• Record Type: Journal Article
• Authors: Stawarz, J. E.; Eastwood, J. P.; Varsani, A.; Ergun, R. E.; Shay, M. A.; Nakamura, R.; Phan, T. D.; Burch, J. L.; Gershman, D. J.; Giles, B. L.; Goodrich, K. A.; Khotyaintsev, Y. V.; Lindqvist, P.‐A.; Russell, C. T.; Strangeway, R. J.; Torbert, R. B.
• Is Part Of: Geophysical research letters. Volume 44:Issue 14(2017)
• Page Start: 7106
• Page End: 7113
• Publication Date: 2017-07-18
• Subjects: Poynting flux -- kinetic Alfvén waves -- bursty bulk flows -- magnetic reconnection -- Earth's plasma sheet; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL073685
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The Magnetospheric Multiscale mission is employed to examine intense Poynting flux directed along the background magnetic field toward Earth, which reaches amplitudes of nearly 2 mW/m 2 . The event is located within the plasma sheet but likely near the boundary at a geocentric distance of 9 R E in association with bulk flow signatures. The fluctuations have wavelengths perpendicular to the magnetic field of 124–264 km (compared to an ion gyroradius of 280 km), consistent with highly kinetic Alfvén waves. While the wave vector remains highly perpendicular to the magnetic field, there is substantial variation of the direction in the perpendicular plane. The field‐aligned Poynting flux may be associated with kinetic Alfvén waves released along the separatrix by magnetotail reconnection and/or the radiation of waves excited by bursty bulk flow braking and may provide a means through which energy released by magnetic reconnection is transferred to the auroral region. Key Points: Extremely strong, earthward Poynting flux observed near plasma sheet boundary layer Evidence of 3‐D effects and subion‐scale structure with large perpendicular wave number consistent with highly kinetic Alfvén waves Poynting flux may be associated with the radiation of waves excited by bursty bulk flow braking and/or the magnetic reconnection separatrix