Auroral Signature of Bow Shock Diffuse Ions 
 
Shen-Wu Chang (1,2) (256-961-7679; changs@cspar.uah.edu) 
Stephen B. Mende (3) 
Joseph F. Fennell (4) 
Harlan E. Spence (5) 
Karel Kudela (6) 
 
1 University of Alabama in Huntsville, Center for Space Plasma and 
  Aeronomic Research, TH S101, Huntsville, AL 35899, United States 
2 National Space Science and Technology Center, Space Science 
  Department/SD50, 320 Sparkman Dr., Huntsville, AL 35805, United 
  States 
3 University of California, Berkeley, Space Sciences Laboratory, 
  Centennial Drive at Grizzly Peak Blvd., Berkeley, CA 94720, United 
  States 
4 The Aerospace Corporation, Mail Stop M2-259, Los Angeles, CA 
  90009, United States 
5 Boston University, Department of Astronomy and Space Physics, 725 
  Commonwealth Ave., Boston, MA 02215, United States 
6 Institute of Experimental Physics, Slovak Academy Sciences, Kosice 
  04353, Slovakia (Slovak Republic) 
 
FUV Spectrographic Imager on board IMAGE spacecraft has the 
capability of detecting Doppler-shifted Lyman-$\alpha$ emissions so 
that in principle it can indirectly monitor the energetic ion precipitations 
into the ionosphere. Concurrent measurements of magnetic fields in the 
solar wind, energetic ions at the quasi-parallel bow shock and proton 
auroral images are examined to reveal the relation between the bow 
shock energetic ion fluxes and photon intensity at the poleward region 
of the dayside auroral zone around the magnetic local noon. The 
upstream diffuse ions possess a significant portion of the total plasma 
energy density. We will show that considerable energy fluxes are 
transported from the bow shock into the ionosphere through the polar 
cusp region to produce the auroral luminosity in the proton auroral 
images. This transport is subjected to the IMF control. 

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Submitted to the Spring 2001 AGU Meeting, Boston, Massachusetts