Solar-minimum quiet time ion energization and outflow in dynamic boundary related coordinates

We report hemispheric average fluxes and energies of outflowing energetic (0.015 < E/q < 33 keV) H + , O + , and He + ions in dynamic boundary-related coordinates, from observations obtained by the Polar/TIMAS instrument near 6,000 km altitude in the southern hemisphere during quiet geomagnetic intervals at solar minimum. We discuss our observations in terms of known energization and transport processes. We find that only a small fraction of energetic ions escape from the ionosphere directly into the polar cap and at quiet times the characteristic energies of escaping H + are between 30 and 300 eV in the cusp region and between 30 eV and 1.2 keV in the midnight sector. For O + we conclude the characteristic energy in the cusp is ~100 eV and between 150 and 600 eV in the midnight sector. Our data suggest that the relative energization and acceleration of O + is significantly different in the noon quadrant. The observations and analysis presented here also suggest that O + has activity dependent transport paths from the ionosphere to the ring current that have not previously been identified.

[1]  W.K. (Bill) Peterson,et al.  The polar wind: Recent observations , 2007 .

[2]  M. Liemohn,et al.  Self-consistent Model of Magnetospheric Ring Current and Propagating Electromagnetic Ion Cyclotron Waves. 2. Wave Induced Ring Current Precipitation and Thermal Electron Heating , 2007 .

[3]  W. Lotko.  The magnetosphere-ionosphere system from the perspective of plasma circulation : A tutorial , 2007 .

[4]  O. W. Lennartsson,et al.  Quiet time solar illumination effects on the fluxes and characteristic energies of ionospheric outflow , 2006 .

[5]  J. Sauvaud,et al.  Characteristics of high altitude oxygen ion energization and outflow as observed by Cluster: a statistical study , 2006 .

[6]  S. Watanabe,et al.  Fate of outflowing suprathermal oxygen ions that originate in the polar ionosphere , 2006 .

[7]  T. Moore,et al.  An examination of the process and magnitude of ionospheric plasma supply to the magnetosphere , 2005 .

[8]  Margaret W. Chen,et al.  Empirical models of the low‐energy plasma in the inner magnetosphere , 2005 .

[9]  C. Russell,et al.  Polar study of ionospheric ion outflow versus energy input , 2005 .

[10]  W.K. (Bill) Peterson,et al.  Estimates of the suprathermal O+ outflow characteristic energy and relative location in the auroral oval , 2005 .

[11]  R. Elphic,et al.  Factors controlling ionospheric outflows as observed at intermediate altitudes , 2005 .

[12]  O. W. Lennartsson,et al.  Solar wind control of Earth's H+ and O+ outflow rates in the 15‐eV to 33‐keV energy range , 2004 .

[13]  W.K. (Bill) Peterson,et al.  Dynamic coordinates for auroral ion outflow , 2004 .

[14]  M. Shay,et al.  Three-species collisionless reconnection: effect of O+ on magnetotail reconnection. , 2004, Physical review letters.

[15]  P. Brandt,et al.  Dynamics of ring current ions as obtained from IMAGE HENA and MENA ENA images , 2004 .

[16]  Edmond C. Roelof,et al.  Global imaging of O+ from IMAGE/HENA , 2003 .

[17]  C. Cully,et al.  Akebono/Suprathermal Mass Spectrometer observations of low‐energy ion outflow: Dependence on magnetic activity and solar wind conditions , 2003 .

[18]  J. Birn,et al.  On the cessation of magnetic reconnection , 2002 .

[19]  M. Fok,et al.  Global ENA observations of the storm mainphase ring current: Implications for skewed electric fields in the inner magnetosphere , 2002 .

[20]  D. Delcourt.  Particle acceleration by inductive electric fields in the inner magnetosphere , 2002 .

[21]  R. Spiro,et al.  Comprehensive computational model of Earth's ring current , 2001 .

[22]  O. W. Lennartsson,et al.  Polar/Toroidal Imaging Mass-Angle Spectrograph observations of suprathermal ion outflow during solar minimum conditions , 2001 .

[23]  Y. Tung.  Erratum: ``Auroral polar cap boundary ion conic outflow observed on FAST'' , 2001 .

[24]  P. Newell,et al.  Boundary‐oriented electron precipitation model , 2000 .

[25]  Lockheed Martin.  POLAR/TIMAS observations of suprathermal ion outflow during solar minimum conditions , 2000 .

[26]  R. Treumann,et al.  Magnetospheric Plasma Sources and Losses , 1999 .

[27]  Paul D. Craven,et al.  Polar wind survey with the Thermal Ion Dynamics Experiment/Plasma Source Instrument suite aboard POLAR , 1998 .

[28]  O. W. Lennartsson,et al.  The seasonal variation of auroral ion beams , 1998 .

[29]  B. A. Whalen,et al.  The Toroidal Imaging Mass-Angle Spectrograph (TIMAS) for the polar mission , 1995 .

[30]  T. Zawistowski,et al.  Hydra — A 3-dimensional electron and ion hot plasma instrument for the POLAR spacecraft of the GGS mission , 1995 .

[31]  T. Mukai,et al.  On the evolution of ion conics along the field line from EXOS D observations , 1993 .

[32]  C. M. Bjorklund,et al.  O+ and He+ restricted and extended (BI‐modal) ion conic distributions , 1992 .

[33]  B. Whalen.  The suprathermal ion mass spectrometer (SMS) for the Akebono (EXOS-D) spacecraft , 1990 .

[34]  J. Drake,et al.  The helium components of energetic terrestrial ion upflows: Their occurrence, morphology, and intensity , 1988 .

[35]  E. G. Shelley,et al.  Survey of 0.1- to 16-keV/e plasma sheet ion composition , 1986 .

[36]  J. Geiss,et al.  The polar ionosphere as a source of energetic magnetospheric plasma , 1982 .

[37]  E. Shelley,et al.  Some general characteristics of upflowing ion beams over the auroral zone and their relationship to auroral electrons , 1981 .

[38]  Robert H. Holzworth,et al.  Mathematical representation of the auroral oval , 1975 .

[39]  T. Holzer,et al.  The polar wind , 1968 .