Accession Number : ADA578386


Title :   Partitioning of Electromagnetic Energy Inputs to the Thermosphere during Geomagnetic Disturbances


Descriptive Note : Final technical rept. 30 Sep 2009-30 Jun 2012


Corporate Author : APPLIED RESEARCH ASSOCIATES INC NASHUA NH


Personal Author(s) : Siebert, Keith D


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a578386.pdf


Report Date : Jun 2012


Pagination or Media Count : 23


Abstract : We investigate a number of fundamental processes that govern thermospheric response to electromagnetic energy inputs. Using a sophisticated numerical model of the coupled solar wind magnetosphere ionosphere thermosphere, we focus on three main subject areas: Poynting flux energy partitioning, horizontal neutral density structures, and feedback of neutral dynamics to the coupled system. Numerical simulations show that approximately 90 per cent of the Poynting flux into the thermosphere goes into Joule heating under steady-state conditions. Thus in a global sense, measurements of Joule heating rates provide a good approximation to total electromagnetic energy input; however, locally this is not always the case. Under southward IMF orientations, local height-integrated Joule heating rates overestimate Poynting flux in regions of high conductance, and underestimate Poynting flux in regions of lower conductance. This confirms the prediction of Richmond (2010).


Descriptors :   *ELECTROMAGNETIC RADIATION , IONOSPHERE , MAGNETOSPHERE , MATHEMATICAL MODELS , SOLAR WIND , THERMOSPHERE


Subject Categories : Radiofrequency Wave Propagation


Distribution Statement : APPROVED FOR PUBLIC RELEASE