Magnetic forces associated with bursty bulk flows in Earth's magnetotail
2015 (English)In: Geophysical Research Letters, ISSN 0094-8276, Vol. 42, no 9, 3122-3128 p.Article in journal (Refereed) Published
We present the first direct measurements of magnetic forces acting on bursty bulk flow plasma in the magnetotail. The magnetic forces are determined using Cluster multispacecraft measurements. We analyze 67 bursty bulk flow (BBF) events and show that the curvature part of the magnetic force is consistently positive, acting to accelerate the plasma toward Earth between approximately 10 and 20 RE geocentrical distances, while the magnetic field pressure gradient increasingly brakes the plasma as it moves toward Earth. The net result is that the magnetic force accelerates the plasma at distances greater than approximately 14 RE, while it acts to decelerate it within that distance. The magnetic force, together with the thermal pressure gradient force, will determine the dynamics of the BBFs as they propagate toward the near-Earth tail region. The determination of the former provides an important clue to the ultimate fate of BBFs in the inner magnetosphere. Key Points Direct measurements of magnetic force acting on BBF plasma BBF plasma is accelerated toward Earth until it reaches 15 RE, then braked Knowledge of the forces on BBFs provides clue to their fate close to Earth.
Place, publisher, year, edition, pages
2015. Vol. 42, no 9, 3122-3128 p.
bursty bulk flows, Cluster, curlometer, multipoint measurements
IdentifiersURN: urn:nbn:se:kth:diva-170293DOI: 10.1002/2015GL063999ISI: 000355878300008ScopusID: 2-s2.0-84930477445OAI: oai:DiVA.org:kth-170293DiVA: diva2:830590
FunderSwedish National Space Board, 78/11A-B
QC 201506302015-06-302015-06-292015-07-03Bibliographically approved