Open AccessStorm time global thermosphere: A driven‐dissipative thermodynamic system
Author(s) -
Burke W. J.,
Lin C. S.,
Hagan M. P.,
Huang C. Y.,
Weimer D. R.,
Wise J. O.,
Gentile L. C.,
Marcos F. A.
Publication year - 2009
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 - 10.1029/2008ja013848
Subject(s) - thermosphere , physics , geomagnetic storm , geophysics , dissipative system , atmospheric sciences , computational physics , ionosphere , solar wind , magnetic field , quantum mechanics
Orbit‐averaged mass densities and exospheric temperatures ∞ inferred from measurements by accelerometers on the Gravity Recovery and Climate Experiment (GRACE) satellites are used to investigate global energy E th and power Π th inputs to the thermosphere during two complex magnetic storms. Measurements show , ∞ , and E th rising from and returning to prevailing baselines as the magnetospheric electric field ɛ VS and the Dst index wax and wane. Observed responses of E th and ∞ to ɛ VS driving suggest that the storm time thermosphere evolves as a driven‐but‐dissipative thermodynamic system, described by a first‐order differential equation that is identical in form to that governing the behavior of Dst. Coupling and relaxation coefficients of the E th , ∞ , and Dst equations are established empirically. Numerical solutions of the equations for ∞ and E th are shown to agree with GRACE data during large magnetic storms. Since ∞ and Dst have the same ɛ VS driver, it is possible to combine their governing equations to obtain estimates of storm time thermospheric parameters, even when lacking information about interplanetary conditions. This approach has the potential for significantly improving the performance of operational models used to calculate trajectories of satellites and space debris and is also useful for developing forensic reconstructions of past magnetic storms. The essential correctness of the approach is supported by agreement between thermospheric power inputs calculated from both GRACE‐based estimates of E th and the Weimer Poynting flux model originally derived from electric and magnetic field measurements acquired by the Dynamics Explorer 2 satellite.