Identification of magnetotail current sheets with MMS magnetometer data based on a moving average algorithm
Presentation Type
Poster
Presenter Format
In Person Meeting Talk
Topic
Dayside Science
Start Date
10-5-2022 5:30 PM
Abstract
The dynamics of the magnetotail current sheet is important to understanding particle acceleration in the Earth’s magnetosphere. Thin current sheets associated with intermittent plasma turbulence, together with high-amplitude electric fields, have been posed as essential ingredients for strong local heating (Stawarz et al. 2015; Ergun et al. 2020). Several statistical studies have been done in the magnetosheath (Chasapis et al., 2017) and in bursty bulk flow (BBF) braking regions (Ergun et al., 2015). These studies employ either the Partial Variance of Increments (PVI) of the magnetic field, or large-amplitude (>50 mV/m) electric fields. However, observations in the distant tail often reveal large-amplitude, spiky electric fields in both lobe-like and sheet-like B fields, which may be associated with either boundary layer plasma mixing or processes related to reconnection. Also, the flapping motion of the tail frequently results in brief lobe and sheet excursion on many temporal scales. Thus, this calls for a multiscale categorization of the processes associated with the lobe and plasma sheet. Previous surveys of lobe-like or sheet-like magnetic fields are often performed with fixed thresholds (Jackman & Arridge, 2011; Coxon et al., 2016) or fitting models (Fairfield & Jones, 1996; Nakamura et al., 2006). PVI search methods, although based on relative calculations, are also dependent on a choice of temporal/spatial scale. Thus, we present a search algorithm based on moving averages of the magnetic field and PVI scalograms to flexibly differentiate lobe/sheet-like fields, which results in a database for future statistical studies. We also present a preliminary survey of the magnetic and electric fields profile in the lobe and current sheet. For future studies, this might be correlated with particle measurements to establish a relation between energy transport between the field and various processes associated with turbulence or reconnection in the magnetotail.
Identification of magnetotail current sheets with MMS magnetometer data based on a moving average algorithm
The dynamics of the magnetotail current sheet is important to understanding particle acceleration in the Earth’s magnetosphere. Thin current sheets associated with intermittent plasma turbulence, together with high-amplitude electric fields, have been posed as essential ingredients for strong local heating (Stawarz et al. 2015; Ergun et al. 2020). Several statistical studies have been done in the magnetosheath (Chasapis et al., 2017) and in bursty bulk flow (BBF) braking regions (Ergun et al., 2015). These studies employ either the Partial Variance of Increments (PVI) of the magnetic field, or large-amplitude (>50 mV/m) electric fields. However, observations in the distant tail often reveal large-amplitude, spiky electric fields in both lobe-like and sheet-like B fields, which may be associated with either boundary layer plasma mixing or processes related to reconnection. Also, the flapping motion of the tail frequently results in brief lobe and sheet excursion on many temporal scales. Thus, this calls for a multiscale categorization of the processes associated with the lobe and plasma sheet. Previous surveys of lobe-like or sheet-like magnetic fields are often performed with fixed thresholds (Jackman & Arridge, 2011; Coxon et al., 2016) or fitting models (Fairfield & Jones, 1996; Nakamura et al., 2006). PVI search methods, although based on relative calculations, are also dependent on a choice of temporal/spatial scale. Thus, we present a search algorithm based on moving averages of the magnetic field and PVI scalograms to flexibly differentiate lobe/sheet-like fields, which results in a database for future statistical studies. We also present a preliminary survey of the magnetic and electric fields profile in the lobe and current sheet. For future studies, this might be correlated with particle measurements to establish a relation between energy transport between the field and various processes associated with turbulence or reconnection in the magnetotail.
