ORCID Profile
0000-0002-5702-5802
Current Organisation
Northumbria University
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Publisher: Copernicus GmbH
Date: 28-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-9481
Abstract: & & & span& In July 2017, the MMS constellation was evolving in the magnetotail with an apogee of 25 Earth radii and an average inter-satellite distance of 10 km (i.e. at electron scales). On 23& /span& & sup& & span& rd& /span& & /sup& & span& of July around 16:19 UT, MMS was located at the edge of the current sheet which was in a quasi-static state. Then, MMS suddenly entered in the central plasma sheet and detected the local onset of a small substorm as indicated by the AE index (~400 nT). Fast plasma flows towards the Earth were measured for about 1 hour starting with a period of quasi-steady flow and followed by a series of saw-tooth plasma jets (& #8220 bursty bulk flows& #8221 ). In the present study, we focus on a short sequence related to the crossing of an ion scale current sheet embedded in a fast earthward flow. The current sheet appears to be corrugated and with a significant guide field (BL/BM~0.5). Tailward propagating electrostatic solitary waves are detected just after the magnetic equator crossing and at the edge of the current sheet. We also analyze in detail an electron vortex magnetic hole also detected at the edge of this current sheet and discuss the Ohm& #8217 s law and energy conversion processes. We find that the energy dissipation associated with the electron vortex is three times greater (0.15nW/m3) than at the current sheet crossing (0.05nW/m3). Based on estimated statistical weight of these vortices we discuss possible consequences for the energy dissipation associated with fast earthward plasma flows.& /span& & &
Publisher: American Astronomical Society
Date: 31-07-2023
Publisher: American Astronomical Society
Date: 31-07-2023
Publisher: American Geophysical Union (AGU)
Date: 09-04-2017
DOI: 10.1002/2016GL072493
Publisher: American Geophysical Union (AGU)
Date: 12-2019
DOI: 10.1029/2019JA027228
Abstract: Magnetic reconnection at the subsolar magnetopause is persistently accompanied by strong fluctuations of the magnetic field ( B ), plasma density ( n ), and all components of the electric field ( E ) and current ( J ). The strongest fluctuations are at frequencies below the lower hybrid frequency and observed in a thin, intense current sheet adjacent to the electron diffusion region. In this current sheet, the background magnitudes of B and n are changing considerably, creating an inhomogeneous plasma environment. We show that the fluctuations in B and n are consistent with an oscillatory displacement of the current sheet in the surface normal direction. The displacement is propagating parallel to the magnetic reconnection X line. Wavelengths are on the order of or longer than the thickness of the current sheet to which they are confined, so we label these waves electromagnetic drift waves. E and J fluctuations are more complex than a simple displacement. They have significant variations in the component along B , which suggest that the drift waves also may be confined along B . The current sheet is supported by an electron drift driven by normal electric field, which, in turn, is balanced by an ion pressure gradient. We suggest that wave growth comes from an instability related to the drift between the electrons and ions. We discuss the possibility that drift waves can displace or penetrate into the electron diffusion region giving magnetic reconnection three‐dimensional structure. Drift waves may corrugate the X line, possibly breaking the X line and generating turbulence.
Publisher: Copernicus GmbH
Date: 04-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-14350
Abstract: & & In July 2017, the MMS constellation was evolving in the magnetotail with an apogee of 25 Earth radii and an average inter-satellite distance of 10 km (i.e. at electron scales). On 23 rd of July around 16:19 UT, MMS was located at the edge of the current sheet which was in a quasi-static state. Then, MMS& br& suddenly entered in the central plasma sheet and detected the local onset of a small substorm as indicated by the AE index (~400 nT). Fast earthward plasma flows were measured for about 1 hour starting with a period of quasi-steady flow and followed by a saw-tooth like series of plasma jets (& #8220 bursty bulk flows& #8221 ). In the present study, we focus on a short sequence related to an ion scale current sheet crossing embedded in a fast earthward flow. We analyse in detail two other kinetic structures in the vicinity of this current sheet: an ion-scale flux rope and an electron vortex magnetic hole and discuss the Ohm& #8217 s law and conversion energy processes.& &
Publisher: American Geophysical Union (AGU)
Date: 12-2019
DOI: 10.1029/2019JA027275
Abstract: We present a model of electromagnetic drift waves in the current sheet adjacent to magnetic reconnection at the subsolar magnetopause. These drift waves are potentially important in governing 3‐D structure of subsolar magnetic reconnection and in generating turbulence. The drift waves propagate nearly parallel to the X line and are confined to a thin current sheet. The scale size normal to the current sheet is significantly less than the ion gyroradius and can be less than or on the order of the wavelength. The waves also have a limited extent along the magnetic field ( B ), making them a three‐dimensional eigenmode structure. In the current sheet, the background magnitudes of B and plasma density change significantly, calling for a treatment that incorporates an inhomogeneous plasma environment. Using detailed examination of Magnetospheric Multiscale observations, we find that the waves are best represented by series of electron vortices, superimposed on a primary electron drift, that propagate along the current sheet (parallel to the X line). The waves displace or corrugate the current sheet, which also potentially displaces the electron diffusion region. The model is based on fluid behavior of electrons, but ion motion must be treated kinetically. The strong electron drift along the X line is likely responsible for wave growth, similar to a lower hybrid drift instability. Contrary to a classical lower hybrid drift instability, however, the strong changes in the background B and n o , the normal confinement to the current sheet, and the confinement along B are critical to the wave description.
Publisher: American Astronomical Society
Date: 31-07-2023
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
No related grants have been discovered for Julia Stawarz.