Investigating the Development of Localized Neutral Density Increases During the 24 August 2005 Geomagnetic Storm

We investigate localized thermospheric neutral density increases (or density spikes) developed during the 24 August 2005 geomagnetic storm and utilize a multi‐instrument database for monitoring the underlying thermospheric, ionospheric, magnetospheric, and solar wind conditions. We study five scenarios occurring under eastward/westward BY dominations and demonstrating the development of density spikes during various events. These scenarios show (1) a northern density spike associated with enhanced antisunward polar flows driven by dayside merging along old‐open field lines during the initial phase, (2) some southern density spikes associated with enhanced sunward auroral flows caused by auroral brightening events during the storm initial phase and main phase, (3) two pairs of southern dayside‐nightside density spike configuration associated with enhanced antisunward polar flows caused by dayside merging and nightside magnetotail reconnections along old‐open field lines during the underlying substorm activity, and (4) a series of enhanced polar sunward flows developed in the polar cap driven by different processes during the recovery phase. We provide a detailed analysis of these events including the specification of underlying field aligned current systems, flow channel types, and auroral forms. Observational results demonstrate the various density spikes and their associated auroral forms and/or flow channels and thus provide a better understanding of their development during this intense geomagnetic storm.

[1]  Timothy Fuller-Rowell,et al.  Modeling the ionosphere-thermosphere response to a geomagnetic storm using physics-based magnetospheric energy input: OpenGGCM-CTIM results , 2016 .

[2]  G. Crowley,et al.  Ionospheric Joule heating, fast flow channels, and magnetic field line topology for IMF By‐dominant conditions: Observations and comparisons with predicted reconnection jet speeds , 2012 .

[3]  H. Carlson,et al.  First‐principles physics of cusp/polar cap thermospheric disturbances , 2012 .

[4]  C. Farrugia,et al.  The pulsed nature of the nightside contribution to polar cap convection: repetitive substorm activity under steady interplanetary driving , 2012 .

[5]  E. Doornbos.  Thermospheric Density and Wind Determination from Satellite Dynamics , 2012 .

[6]  C. Farrugia,et al.  Substorms and polar cap convection: the 10 January 2004 interplanetary CME case , 2012 .

[7]  C. Farrugia,et al.  Dayside and nightside contributions to cross-polar cap potential variations: The 20 March 2001 ICME case , 2011 .

[8]  G. Crowley,et al.  Extreme Poynting flux in the dayside thermosphere: Examples and statistics , 2011 .

[9]  D. Knipp,et al.  The relation between dayside local Poynting flux enhancement and cusp reconnection , 2011 .

[10]  J. Kan,et al.  Simulations of observed auroral brightening caused by solar wind dynamic pressure enhancements under different interplanetary magnetic field conditions , 2011 .

[11]  Eelco Doornbos,et al.  Neutral Density and Crosswind Determination from Arbitrarily Oriented Multiaxis Accelerometers on Satellites , 2010 .

[12]  C. Farrugia,et al.  Polar cap convection/precipitation states during Earth passage of two ICMEs at solar minimum , 2010 .

[13]  H. Lühr,et al.  Plasma convection jets near the poleward boundary of the nightside auroral oval and their relation to Pedersen conductivity gradients , 2010 .

[14]  G. Crowley,et al.  Thermospheric density enhancements in the dayside cusp region during strong BY conditions , 2010 .

[15]  C. Farrugia,et al.  Plasma flow channels at the dawn/dusk polar cap boundaries: momentum transfer on old open field lines and the roles of IMF B y and conductivity gradients , 2008 .

[16]  B. Anderson,et al.  High‐latitude ionosphere convection and Birkeland current response for the 15 May 2005 magnetic storm recovery phase , 2008 .

[17]  Charles J. Farrugia,et al.  Poleward moving auroral forms (PMAFs) revisited: responses of aurorae, plasma convection and Birkeland currents in the pre- and postnoon sectors under positive and negative IMF B y conditions , 2007 .

[18]  Charles J. Farrugia,et al.  Role of poleward moving auroral forms in the dawn-dusk auroral precipitation asymmetries induced by IMF By , 2007 .

[19]  Charles J. Farrugia,et al.  Dayside aurorae and polar arcs under south-east IMF orientation , 2006 .

[20]  Hong Wang,et al.  On the generation of enhanced sunward convection and transpolar aurora in the high-latitude ionosphere by magnetic merging , 2005 .

[21]  S. Mende,et al.  Global auroral responses to abrupt solar wind changes: Dynamic pressure, substorm, and null events , 2005 .

[22]  C. Farrugia,et al.  Detailed dayside auroral morphology as a function of local time for southeast IMF orientation: implications for solar wind-magnetosphere coupling , 2004 .

[23]  W. J. Burke,et al.  Transient sheets of field-aligned current observed by DMSP during the main phase of a magnetic superstorm , 2004 .

[24]  M. Watkins,et al.  The gravity recovery and climate experiment: Mission overview and early results , 2004 .

[25]  L. Grunwaldt,et al.  Thermospheric up‐welling in the cusp region: Evidence from CHAMP observations , 2004 .

[26]  L. Blomberg,et al.  Lobe cell convection and field‐aligned currents poleward of the region 1 current system , 2002 .

[27]  C. Reigber,et al.  CHAMP mission status , 2002 .

[28]  D. Weimer.  Maps of ionospheric field‐aligned currents as a function of the interplanetary magnetic field derived from Dynamics Explorer 2 data , 2001 .

[29]  K. Morzinski,et al.  Two-satellite observations of substorm injections at geosynchronous orbit , 2001 .

[30]  T. Hughes,et al.  Auroral zone dayside precipitation during magnetic storm initial phases , 2001 .

[31]  J. Moen,et al.  Dynamic cusp aurora and associated pulsed reverse convection during northward interplanetary magnetic field , 2000 .

[32]  J. M. Ruohoniemi,et al.  Large-scale imaging of high-latitude convection with Super Dual Auroral Radar Network HF radar observations , 1998 .

[33]  J. Birn,et al.  Substorm electron injections: Geosynchronous observations and test particle simulations , 1998 .

[34]  J. Birn,et al.  Substorm ion injections: Geosynchronous observations and test particle orbits in three-dimensional dynamic MHD fields , 1997 .

[35]  H. Hayakawa,et al.  Cross polar cap diameter and voltage as a function of PC index and interplanetary quantities , 1996 .

[36]  D. Weimer,et al.  Models of high‐latitude electric potentials derived with a least error fit of spherical harmonic coefficients , 1995 .

[37]  Frederick J. Rich,et al.  Large-scale convection patterns observed by DMSP , 1994 .

[38]  G. Gisler,et al.  High‐Z energetic particles at geosynchronous orbit during the Great Solar Proton Event Series of October 1989 , 1992 .

[39]  N. Maynard,et al.  Empirical high‐latitude electric field models , 1987 .

[40]  P. Reiff,et al.  IMF By-dependent plasma flow and Birkeland currents in the dayside magnetosphere: 2. A global model for northward and southward IMF , 1985 .

[41]  N. A. Saflekos,et al.  Field-aligned currents in the south polar cusp and their relationship to the interplanetary magnetic field , 1978 .

[42]  T. Potemra,et al.  The amplitude distribution of field-aligned currents at northern high latitudes observed by TRIAD. Interim report , 1975 .

[43]  J. Heppner.  Polar‐cap electric field distributions related to the interplanetary magnetic field direction , 1972 .

[44]  J. Dungey.  Interplanetary Magnetic Field and the Auroral Zones , 1961 .

[45]  Etienne Renotte,et al.  Far ultraviolet imaging from the IMAGE spacecraft. 1. System design , 2000 .

[46]  Harald U. Frey,et al.  Far ultraviolet imaging from the IMAGE spacecraft. 2. Wideband FUV imaging , 2000 .

[47]  Harald U. Frey,et al.  Far Ultraviolet Imaging from the Image Spacecraft , 2000 .

[48]  R. G. Musgrove,et al.  Solar-wind dependencies of high-latitude convection and precipitation , 1986 .