Ionospheric energy input as a function of solar wind parameters: global MHD simulation results

M Palmroth*, P Janhunen, TI Pulkkinen, HEJ Koskinen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

We examine the global energetics of the solar wind magnetosphere-ionosphere system by using the global MHD simulation code GUMICS-4. We show simulation results for a major magnetospheric storm (6 April 2000) and a moderate substorm (15 August 2001). The ionospheric dissipation is investigated by determining the Joule heating and precipitation powers in the simulation during the two events. The ionospheric dissipation is concentrated largely on the dayside cusp region during the main phase of the storm period, whereas the nightside oval dominates the ionospheric dissipation during the substorm event. The temporal variations of the precipitation power during the two events are shown to correlate well with the commonly used AE-based proxy of the precipitation power. The temporal variation of the Joule heating power during the substorm event is well-correlated with a commonly used AE-based empirical proxy, whereas during the storm period the simulated Joule heating is different from the empirical proxy. Finally, we derive a power law formula, which gives the total ionospheric dissipation from the solar wind density, velocity and magnetic field z-component and which agrees with the simulation result with more than 80% correlation.

Original languageEnglish
Pages (from-to)549-566
Number of pages18
JournalAnnales Geophysicae
Volume22
Issue number2
Publication statusPublished - 2004
MoE publication typeA1 Journal article-refereed

Keywords

  • ionosphere
  • modeling and forecasting
  • magnetospheric physics
  • magnetosphere-ionosphere interactions
  • storms and substorms
  • INTERPLANETARY MAGNETIC-FIELD
  • MAGNETOSPHERE
  • DEPOSITION
  • ELECTRONS
  • SUBSTORMS
  • STORM

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