1. HENA: IMPLICATIONS FOR STRONG E-FEILDS (and some more...)
P. C:son Brandt, D. G. Mitchell, R. Demajistre, E. C. Roelof
The Johns Hopkins University Applied Physics Laboratory

2. OUTLINE E-FIELD DURING MAINPHASES
1. Storm mainphases: HENA observes peak at post-midnight.
2. Comparison with models [M. -C. Fok].
3. Why? [M. Liemohn]
STORM-SUBSTORM UPDATE
GLOBAL SAWTOOTH OSCILLATIONS [R. Skoug]

9. DIFFERENCES COMPARISON WITH WEIMER MODEL (FOK):
Peak of ion distribution is skewed in MLT 16- ~200 keV.
Peak is slightly further in.
Configuration appears less sensitive to disturbances.
Skewing appears to increase with epsilon parameter of IMF.

10. WHY NOT SKEWING?

13. CONCLUSIONS
The E-field of the inner magnetosphere are skewed during storm mainphases.
Possibly due to the additional ring-current driven potentials [Liemohn].
One would expect the skewing to be established as the partial ring current develops...
...or...counter example: 21 Oct 2001.

14. STORM-SUBSTORM
Substorms in the 4 Oct 2000 mainphase appear as "ripples on the surface".
4 Oct 2000, 21 Oct 2001: Substorms seems to appear at the beginning of storms: What are their role inestablishing the first partial ring current?

17. GLOBAL SAWTOOTH OSCILLATIONS???
Ruth Skoug will talk more.
Global dipolarization events are sometimes observed during storm mainphase.
HENA can confirm that ion distributions are enhanced during ~20 min, GLOBALLY!
What is going on???
MOVIE 11 Aug 2000.

18. SUMMARY How is the skewed E-field formed?
Are substorms "ripples on the surface" during magnetic storms? O+ gradual build-up?
Are the global sawtooth oscillations global dipolarizations [Skoug, Borovsky,..]?
MODELERS: ENA simulation code available.