# Presentation: 653662

## Location of very intense KAW, Electrostatic ion cyclotron waves, other small scale wave structuresJohn Wygant

- There are several regions where RBSP could expect to see large amplitude kinetic Alfven waves,  and intense low frequency electrostatic waves. These regions are:
- 1) During substorm injection events observed on the night-side from 4.5 Re to > 6 Re over 6-18 MLT.
- 2) At stationary convection and pressure boundaries and FAC  at the outer edge of the ring current. This boundary is also spatially extensive in magnetic local time and is present between 4.0 and >6 Re.
- Although, there are specific examples of such waves in association with boundaries and injection events, There is very little statistical information on the spatial dimensions of the associated wave fields. All of the macroscopic structures tend to   have spatial scales  from 4.5 Re to > 6 Re over local times 6-18 MLT. The occurrenc frequency on the dayside is not well documented .
_**Since this is a broad spatial region, it is not a discriminator of different orbits as long as the apogee is above  L=5.5 and within MLAT 30 degrees of equator.**_

## Rough Statements about two spacecraft measurements

Two spacecraft can provide the following information on the structure and dynamics of these waves fields when separated by 2000 km to 6  hours in MLT:

1) The two RBSP spacecraft will measure the azimuthal spatial scales of the wave fields when separated over azimuthal distances of 2000 to 50,000 km.

2) The two RBSP spacecraft will  measure the radial scale sizes of the wave fields over distances of 2000 to 12.000 km if they are in nearly similar orbits those apogees have not precessed relative to one another.

3) They will probably not be close enough for long enough periods to resolve the azimuthal or radial coherence length of individual waves (10-1000 km)

- Two spacecraft can provide the following information on the structure and dynamics of these waves fields when separated by 2000 km to 6  hours in MLT:
- 1) The two RBSP spacecraft will measure the azimuthal spatial scales of the wave fields when separated over azimuthal distances of 2000 to 50,000 km.
- 2) The two RBSP spacecraft will  measure the radial scale sizes of the wave fields over distances of 2000 to 12.000 km if they are in nearly similar orbits those apogees have not precessed relative to one another.
- 3) They will probably not be close enough for long enough periods to resolve the azimuthal or radial coherence length of individual waves (10-1000 km)

## Statistics on occurrence frequency/location is limited but individual event studies suggest intervals of intense small scale waves coincide with  substorm injection fronts and convection boundaries often in assoication with major geomagnetic storms . Below is a study by Rowland (PhD thesis) in MLT and L value (not Re) of substorm locations.

- CRRES observed 137 events with Eyz > 15 mV/m, at local times ranging from ~1800 to 2400 LT.

- Sun

- Rowland
- unpublished

## Injection Front: prompt energization of ~ 1 MeV electrons near 
R=4.28 Local midnight
Top panels
Large scale Ey gse, Bz gse
Drift Echo signature in energetic particles
Intense 100 mV/m(ptp) electric field turbulence in Ey and Ez gse  (0.2 to 10 Hz)
Possible stochastic transit time acceleration due to bounce between mirror points

- R=4.28 Local midnight
- Top panels
- Large scale Ey gse, Bz gse
- Drift Echo signature in energetic particles
- Intense 100 mV/m(ptp) electric field turbulence in Ey and Ez gse  (0.2 to 10 Hz)
- Possible stochastic transit time acceleration due to bounce between mirror points

## Existence of intense small scale 30 Hz electrostatic waves in inner magnetosphere imbedded in Alfven wave fields

- Enhancement of Energetic electrons
- (CEPPAD-CDAWEB)
- Hydra electrons an Ions
- Turbulent electric fields, Alfven wave,s and Poynting flux
- Burst recording of intense low frequency
- turbulence
-  E~ 400 mV/m ptp;  perp to B,  ~30 Hz :
- Two spacecraft comparisons allow us to understand
- spatial extent of intense low frequency wave fields and relation to larger scale  boundaries and structures
-  through comparison of E&B  spectra and cross
- spectra (DSP board) parallel and perpendicular to B