Statistical Survey of Magnetic Forces Associated With Earthward Bursty Bulk Flows Measured by MMS 2017-2021Show others and affiliations
2023 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 128, no 5, article id e2022JA031094Article in journal (Refereed) Published
Abstract [en]
We investigate the magnetic forces (the magnetic pressure gradient force, the curvature force, and their sum the j x B-force) associated with earthward bursty bulk flows (BBFs) using Magnetospheric Multiscale (MMS) data from five tail seasons (2017-2021). For the first time, the magnetic forces are inferred downtail of XGSM = -20 R-E and in the GSM XY and YZ planes. The results suggest that BBFs tend to be accelerated earthward by the magnetic pressure gradient force tailward of similar to 19 R-E and decelerated closer to that distance in the 2017-2018 data. The force magnitudes increase with distance. This is in accordance with earlier Cluster results. In the 2019-2021 data, the pressure gradient force magnitudes are generally smaller and no clear distance for the acceleration reversal can be determined. The curvature forces for both 2017-2018 and 2019-2021 BBFs indicate earthward acceleration independent of distance, consistent with the Cluster measurements. The sum, the j x B-force, suggests for the 2017-2018 BBFs earthward acceleration tailward of XGSM similar to 15 R-E and deceleration within that distance, also consistent with Cluster. In contrast, the 2019-2021 BBFs show general earthward acceleration by j x B independent of distance. In the GSM XY plane, the average (j x B)(xy) vectors are earthward, and in the premidnight and postmidnight dawnward for the 2017-2018 BBFs. For 2019-2021, the average (j x B)(xy) vectors have components toward the tail center. In the GSM YZ plane, the average (j x B)(yz) vectors are toward the neutral sheet.
Place, publisher, year, edition, pages
American Geophysical Union (AGU) , 2023. Vol. 128, no 5, article id e2022JA031094
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
URN: urn:nbn:se:kth:diva-329910DOI: 10.1029/2022JA031094ISI: 001000332300001Scopus ID: 2-s2.0-85160392932OAI: oai:DiVA.org:kth-329910DiVA, id: diva2:1774572
Note
QC 20230626
2023-06-262023-06-262023-06-26Bibliographically approved