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arXiv · 2503.07905

Investigating the Dependence of Normalized Reconnection Rate on Upstream Plasma Parameters

S. V. Heuer·K. J. Genestreti·Y. -H Liu·J. R. Shuster·X. Li·R. B. Torbert·J. L. Burch
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Abstract

We present the results of a multi-event study of the normalized reconnection rate integrating events spanning the three primary regimes of reconnection observed by the Magnetospheric Multiscale (MMS) mission. We utilize a new method for determining the normalized reconnection rate with fewer sources of uncertainty by estimating the current sheet aspect ratio with magnetic field gradients, which are very well measured by MMS. This method is time-dependent and also captures spatiotemporal variation in the current sheet aspect ratio. After demonstrating this technique is valid in the guide field and asymmetric regimes of reconnection, we investigate any relationships between the normalized rate, aspect ratio, and spatiotemporal aspect ratio variability on the guide field, spatiotemporal variability of the upstream magnetic field, and upstream magnetic field and density asymmetry. We find no dependence of reconnection rate on upstream conditions, with the only statistically significant correlations between the spatiotemporal variability in the aspect ratio and the spatiotemporal angular variability in the upstream reconnecting component of the magnetic field. This result is consistent with previous work that found the spatiotemporal ``patchiness'' of energy conversion within the electron diffusion region is correlated with the same measure of spatiotemporal variability of the inflow magnetic field used here. Additionally, this analysis suggests that under typical magnetospheric conditions for density and magnetic field asymmetry with steady upstream magnetic field, the normalized reconnection rate is constant with a slight increase for higher guide fields, which may be significant in predicting the terrestrial effects of space weather by providing insight into the efficiency of solar wind-magnetospheric coupling.

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S. V. Heuer, K. J. Genestreti, Y. -H Liu, J. R. Shuster, X. Li, R. B. Torbert, J. L. Burch. 2025-08-15. Investigating the Dependence of Normalized Reconnection Rate on Upstream Plasma Parameters. https://arxiv.org/abs/2503.07905

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