Structure of energy flux densities in Earth's magnetotail reconnection regions: Bridging simulation and observation

Cara L. Waters; Jonathan P. Eastwood; Harry C. Lewis; Naïs Fargette; Marit Øieroset; Tai D. Phan; David L. Newman; Martin V. Goldman

arXiv · 2611.02870

Structure of energy flux densities in Earth's magnetotail reconnection regions: Bridging simulation and observation

Cara L. Waters·Jonathan P. Eastwood·Harry C. Lewis·Naïs Fargette·Marit Øieroset·Tai D. Phan·David L. Newman·Martin V. Goldman

View original source ↗Read source document ↗Export metadata ↓

Abstract

Magnetic reconnection is important in both space and laboratory contexts because it changes the topology of magnetic fields and converts magnetic energy into particle energies. Establishing where this energy conversion occurs is critical for understanding how reconnection partitions energy. Using a novel machine learning approach based on simulations that explicitly identifies the separatrix regions for the first time, the partition of energy flux densities within the magnetic reconnection site is evaluated through statistical study of magnetotail reconnection events observed in situ. The separatrices are found to have the largest electron energy flux densities, roughly twice those in the exhaust, and Poynting flux densities about four times those in the inflows, whereas typical ion enthalpy flux densities are largest in the exhaust. The separatrices are therefore sites of intense electron and electromagnetic energy transport, although their small thickness means that the exhaust may still carry most of the total energy flux.

Explore related subjects

physics.space-ph physics.plasm-ph

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Cara L. Waters, Jonathan P. Eastwood, Harry C. Lewis, Naïs Fargette, Marit Øieroset, Tai D. Phan, David L. Newman, Martin V. Goldman. 2026-11-02. Structure of energy flux densities in Earth's magnetotail reconnection regions: Bridging simulation and observation. https://arxiv.org/abs/2611.02870

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

A living catalog of stream interaction regions in the Parker Solar Probe era

Stream interaction regions (SIRs) and corotating interaction regions (CIRs) are important phenomena in heliospheric physics. These large-scale structures vary temporally and spatially, both in latitude and with radial distance. The additions of Parker Solar Probe (PSP) and Solar Orbiter have allowed for investigations into the radial evolution of these structures over a wide range of heliocentric distances for the first time since the Helios era. To better enable investigations of SIRs and CIRs within the inner heliosphere, we have developed a living catalog of SIR and CIR observations by Parker Solar Probe with corresponding observations by STEREO-A as well as ACE and Wind at 1 au. The methodology used for the identification of events and the generation of this catalog, the initial catalog of PSP observations spanning orbits one through five along with corresponding 1 au observations, and information on accessing the living catalog for future studies is described. This list of SIR and CIR events from PSP and corresponding observations from other heliophysics missions will enable case studies utilizing unique orbital arrangements, as well as aid in future statistical studies to further understand the properties and evolution of these structures.

physics.space-ph↗

arXiv2026

Delayed maximum energy solar energetic particle events: Statistical analysis from Solar Orbiter

Investigations of solar energetic particles (SEPs) have long utilized the dispersive nature of onset times, as in, the earlier arrival of higher-energy particles compared to lower-energy particles, to infer information such as the path length to the acceleration site at the time of initial particle release. However, recent observations by Solar Orbiter and Parker Solar Probe have begun to characterize SEP events with an apparent delay in arrival times of the higher energy portion of the particle distribution, above a critical energy separating the delayed particles from that of the typical velocity dispersion signature at lower energies. Features of these delayed maximum energy (DME) SEP events, sometimes referred to as "inverse velocity dispersion" events, could provide new insight into the impacts of magnetic connectivity to locations along an expanding coronal mass ejection-driven (CME-driven) shock wave, variations of acceleration along the shock surface, and transport effects in the inner heliosphere. This study focuses on the occurrence rate and characteristics of DME events observed by Solar Orbiter relative to their footpoint locations with respect to the initial flare site. These DME events show a bias in occurrence rate towards events when the observer's footpoints were westward of the associated flare location. Additionally, estimated locations at which the highest-energy particles of DME events are released into the flux tube suggest continued release of increasingly higher-energy particles from the CME-driven shock into the connected flux tube well into the inner heliosphere. This indicates that DME events could be attributed to inner heliospheric effects and are not actually coronal in origin. This finding is consistent with previous observations and interpretations of SEP events connected westward of the associated flare.

physics.space-ph↗

arXiv2026

A heteroskedasticity and autocorrelation consistent test for process noise calibration of Kalman filters in multi-sensor orbit determination

Process noise calibration is a central problem in sequential orbit determination. If the process noise covariance is too small the filter is overconfident, and if it is too large it is overconservative. In both cases the estimation error grows and the reported covariance stops describing it, which affects downstream products such as conjunction assessment or re-entry prediction. No widely adopted method diagnoses the calibration in multi-sensor settings, where measurements of different type and dimension must enter a single consistency metric. This work presents the Heteroskedasticity and Autocorrelation Consistent Dimensionless Averaged Normalised Innovation Squared (HAC-DANIS) test, which evaluates process noise calibration from the innovation sequence of the filter, without ground truth. The normalised innovation squared (NIS) of each measurement is divided by its dimension, which puts sensors of any dimension on a common scale, and the standard error of the averaged sequence is obtained with the heteroskedasticity and autocorrelation consistent (HAC) Newey--West estimator, which accounts for the sensor-dependent variance of the sequence and for the serial correlation left by a miscalibrated filter or an imperfect dynamical model. Under mixing and moment conditions the statistic is asymptotically standard normal for a calibrated filter, and for a miscalibrated one its sign indicates the direction of the miscalibration. The autocorrelation function of the normalised sequence complements the test with a characterisation of the mistuning regime. Applied to an unscented Kalman filter processing simulated laser, telescope and radar observations of four satellites in low Earth orbit, the test rejects the eight miscalibrated process noise configurations with the sign of their miscalibration and does not reject the four calibrated with it.

physics.space-ph↗