Imperial College London

Dr Jonathan P. Eastwood

Faculty of Natural SciencesDepartment of Physics

Senior Lecturer



+44 (0)20 7594 8101jonathan.eastwood Website




6M63Blackett LaboratorySouth Kensington Campus






BibTex format

author = {Fadanelli, S and Lavraud, B and Califano, F and Jacquey, C and Vernisse, Y and Kacem, I and Penou, E and Gershman, D and Dorelli, J and Pollock, C and Giles, B and Avanov, L and Burch, J and Chandler, M and Coffey, V and Eastwood, J and Ergun, R and Farrugia, C and Fuselier, S and Genot, V and Grigorenko, E and Hasegawa, H and Khotyaintsev, Y and Le, Contel O and Marchaudon, A and Moore, T and Nakamura, R and Paterson, W and Phan, T and Rager, A and Russell, C and Saito, Y and Sauvaud, J-A and Schiff, C and Smith, S and Toledo, Redondo S and Torbert, R and Wang, S and Yokota, S},
doi = {10.1029/2019JA026747},
journal = {Journal of Geophysical Research: Space Physics},
pages = {6850--6868},
title = {Four-spacecraft measurements of the shape and dimensionality of magnetic structures in the near-Earth plasma environment},
url = {},
volume = {124},
year = {2019}

RIS format (EndNote, RefMan)

AB - We present a new method for determining the main relevant features of the local magnetic field configuration, based entirely on the knowledge of the magnetic field gradient using four- spacecraft measurements. The method, named “Magnetic Configuration Analysis” (MCA), estimates the spatial scales on which the magnetic field varies locally. While it directly derives from the well-known Magnetic Directional Derivative (MDD) and Magnetic Rotational Analysis (MRA) procedures (Shi et al., 2005, doi:10.1029/2005GL022454; Shen et al., 2007, doi:10.1029/2005JA011584), MCA was specifically designed to address the actual magnetic field geometry. By applying MCA to multi-spacecraft data from the MMS satellites, we perform both case and statistical analyses of local magnetic field shape and dimensionality at very high cadence and small scales. We apply this technique to different near-Earth environments and define a classification scheme for the type of configuration observed. While our case studies allow us to benchmark the method with those used in past works, our statistical analysis unveils the typical shape of magnetic configurations and their statistical distributions. We show that small-scale magnetic configurations are generally elongated, displaying forms of cigar and blade shapes, but occasionally being planar in shape like thin pancakes (mostly inside current sheets). Magnetic configurations, however, rarely show isotropy in their magnetic variance. The planar nature of magnetic configurations and, most importantly, their scale lengths strongly depend on the plasma β parameter. Finally, the most invariant direction is statistically aligned with the electric current, reminiscent of the importance of electromagnetic forces in shaping the local magnetic configuration
AU - Fadanelli,S
AU - Lavraud,B
AU - Califano,F
AU - Jacquey,C
AU - Vernisse,Y
AU - Kacem,I
AU - Penou,E
AU - Gershman,D
AU - Dorelli,J
AU - Pollock,C
AU - Giles,B
AU - Avanov,L
AU - Burch,J
AU - Chandler,M
AU - Coffey,V
AU - Eastwood,J
AU - Ergun,R
AU - Farrugia,C
AU - Fuselier,S
AU - Genot,V
AU - Grigorenko,E
AU - Hasegawa,H
AU - Khotyaintsev,Y
AU - Le,Contel O
AU - Marchaudon,A
AU - Moore,T
AU - Nakamura,R
AU - Paterson,W
AU - Phan,T
AU - Rager,A
AU - Russell,C
AU - Saito,Y
AU - Sauvaud,J-A
AU - Schiff,C
AU - Smith,S
AU - Toledo,Redondo S
AU - Torbert,R
AU - Wang,S
AU - Yokota,S
DO - 10.1029/2019JA026747
EP - 6868
PY - 2019///
SN - 2169-9380
SP - 6850
TI - Four-spacecraft measurements of the shape and dimensionality of magnetic structures in the near-Earth plasma environment
T2 - Journal of Geophysical Research: Space Physics
UR -
UR -
VL - 124
ER -