Applying Magnetic Curvature to MMS Data to Identify Thin Current Sheets Relative to Tail Reconnection

Area of Science:

• Space Physics
• Plasma Physics
• Astrophysics

Background:

• Thin current sheets (TCSs) are crucial for triggering magnetic reconnection.
• Magnetic reconnection X-lines in the magnetotail often occur duskward of midnight.
• Previous studies have explored current sheet thickness, but not broadly across radial distances.

Purpose of the Study:

• To calculate the thickness of the cross-tail neutral sheet relative to ion gyroradius using MMS data.
• To investigate the radial and azimuthal distribution of TCSs in the magnetotail.
• To compare findings with current theories and simulations of current sheet thinning.

Main Methods:

• Utilized the Magnetospheric Multiscale (MMS) mission's tetrahedral formation (2017-2020) to analyze magnetotail data.
• Calculated the thickness of the cross-tail neutral sheet relative to the ion gyroradius.
• Compared MMS observations with existing theories and simulation results.

Main Results:

• MMS data revealed significantly longer durations in ion-scale TCSs in the pre-midnight sector compared to the post-midnight sector.
• This asymmetry persisted despite similar plasma sheet dwell times in both sectors.
• The dawn-dusk asymmetry in Ion Diffusion Regions, linked to TCSs, was also examined.

Conclusions:

• The pre-midnight sector is a preferential location for ion-scale thin current sheets in the magnetotail.
• This spatial asymmetry likely influences the distribution and characteristics of magnetic reconnection events.
• Findings provide new insights into the mechanisms governing magnetotail current sheet dynamics and their relation to space weather.