HR: 1340h
AN: SM13A-1193    [Abstracts]
TI: Mid-latitude hiss and plasmaspheric notch
AU: * Masson, A
EM: Arnaud.Masson@esa.int
AF: SCI-SH, RSSD, European Space Agency, Keplerlaan,1, Noordwijk, 2201 AZ Netherlands
AU: Inan, U
EM: inan@stanford.edu
AF: STAR Laboratory, Stanford University, Stanford, CA 94305 United States
AU: Laakso, H
EM: Harri.Laakso@esa.int
AF: SCI-SH, RSSD, European Space Agency, Keplerlaan,1, Noordwijk, 2201 AZ Netherlands
AU: Decreau, P
EM: pdecreau@cnrs-orleans.fr
AF: LPCE/CNRS, Universite d'Orleans, 3A avenue de la recherche scientifique, Orleans, 45071 France
AU: Santolik, O
EM: os@matfyz.cz
AF: Charles University, V Holesovickach 2, Prague, 18000 Czech Republic
AB: A newly identified whistler mode ELF/VLF emission, observed by the Cluster satellites, will be presented. In the vicinity of the plasmapause, around the geomagnetic equator, the four Cluster satellites often observe banded hiss-like electromagnetic emissions (BHE). Their frequency bandwidth is always in between the lower hybrid resonance and the electron gyrofrequency, from 2 kHz to 10 kHz. Based on two years of data measured by three waves experiments on Cluster (WHISPER, STAFF and WBD), the following properties of the BHE waves have been deduced: (i) their location is strongly correlated with the position of the plasmapause, (ii) no MLT dependence has been found, (iii) their spectral width is generally 1 to 2 kHz, and (iv) the central frequency of their emission band varies from 2 kHz to 10 kHz. All these features suggest that BHE are in fact mid-latitude hiss emissions (MLH). MLH have been rarely observed on a regular basis at such altitude. Based on this survey, the central frequency of mid-latitude hiss is shown to be correlated with the Kp index. This suggests either that these banded emissions are generated in a given f/fce range, or that there is a Kp dependent Doppler shift between the satellites and a possible moving source of the MLH Mid-latitude hiss case events observed within density depletion known as plasmaspheric notch (observed by the EUV instrument on IMAGE) will be presented. A recent study showed that plasmaspheric notch plays a crucial role in the generation of higher frequency emissions such as kilometric continuum. The role of plasmaspheric notch in the generation and/or the amplification of mid-latitude hiss will be addressed.
DE: 6964 Radio wave propagation
DE: 2768 Plasmasphere
DE: 2772 Plasma waves and instabilities
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting