Polynomial reconstruction of the magnetic field around the Magnetospheric Multiscale (MMS) spacecraft
Abstract
We describe methods for polynomial reconstruction of the magnetic field close to a cluster of 4 spacecraft using the spacecraft measurements of the magnetic field and current density as input; then we use these methods to reconstruct the magnetic field observed during magnetic reconnection events observed by the Magnetospheric Multiscale (MMS) spacecraft and to data from virtual MMS spacecraft flying through a simulation of magnetopause reconnection. The models yield 2D and 3D visualizations of the magnetic field, and show interesting dynamics, such as stretched magnetic fields and secondary reconnection. Different models vary in complexity between a 12 parameter Linear model and a 27 parameter Quadratic model, that has the full quadratic expansion except that the second derivative with respect to the Minimum Directional Derivative (MDD) minimum gradient coordinate m has been neglected. For MMS events for which the magnetic structure is approximately two-dimensional, upper bounds for errors can be estimated by using only three spacecraft to evaluate a model, and then comparing the model value with that observed at the position of the fourth spacecraft. For one magnetotail reconnection event, the resulting errors in the magnetic field are typically less than 0.1 nT. Reconstructions of simulated data are also used to test the methods. The reconstructions of simulated data for a magnetopause reconnection event are accurate on the magnetosheath side of the current sheet, where the magnetic field is more distorted, but poor on the magnetosphere side, where the parameters of the models are determined from small variations in the magnetic field.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM23B..03D
- Keywords:
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- 2723 Magnetic reconnection;
- MAGNETOSPHERIC PHYSICS;
- 2744 Magnetotail;
- MAGNETOSPHERIC PHYSICS;
- 7526 Magnetic reconnection;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7835 Magnetic reconnection;
- SPACE PLASMA PHYSICS