Open AccessC/NOFS measurements of magnetic perturbations in the low‐latitude ionosphere during magnetic storms
Author(s) -
Le Guan,
Burke William J.,
Pfaff Robert F.,
Freudenreich Henry,
Maus Stefan,
Lühr Hermann
Publication year - 2011
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011ja017026
Subject(s) - magnetometer , ring current , geomagnetic storm , ionosphere , geophysics , dipole model of the earth's magnetic field , physics , magnetic field , space weather , geodesy , geomagnetic latitude , local time , latitude , spacecraft , geology , earth's magnetic field , interplanetary magnetic field , solar wind , astronomy , statistics , mathematics , quantum mechanics
The Vector Electric Field Investigation suite on the C/NOFS satellite includes a fluxgate magnetometer to monitor the Earth's magnetic fields in the low‐latitude ionosphere. Measurements yield full magnetic vectors every second over the range of ±45,000 nT with a one‐bit resolution of 1.37 nT (16 bit A/D) in each component. The sensor's primary responsibility is to support calculations of both V × B and E × B with greater accuracy than can be obtained using standard magnetic field models. The data also contain information about large‐scale current systems that, when analyzed in conjunction with electric field measurements, promise to significantly expand understanding of equatorial electrodynamics. We first compare in situ measurements with the POMME (Potsdam Magnetic Model of the Earth) model to establish in‐flight sensor “calibrations” and to compute magnetic residuals. At low latitudes the residuals are predominately products of the storm time ring current. Since C/NOFS provides a complete coverage of all local times every 97 min, magnetic field data allow studies of the temporal evolution and local time variations of storm time ring current. The analysis demonstrates the feasibility of using instrumented spacecraft in low‐inclination orbits to extract a timely proxy for the provisional Dst index and to specify the ring current's evolution.