Electron acceleration observed by the FAST satellite within the IAR during a 3 Hz modulated EISCAT heater experiment
نویسندگان
چکیده
A quantitative analysis is presented of the FAST satellite electric field and particle flux data during an EISCAT heating experiment run on 8 October 1998. Radio frequency heating, modulated at 3 Hz, launched ULF waves from the ionosphere into the lower magnetosphere. The ULF waves were observed in FAST data and constituted the first satellite detection of artificially excited Alfvénic ULF waves. The downward electron flux data for this event contain the first observations of electrons undergoing acceleration within the Ionospheric Alfvén Resonator (IAR) due to parallel electric fields associated with an artificially stimulated Alfvén wave. The time history and spectral content of the observed downward electron fluxes is investigated by considering the effects of a localised parallel electric field. Furthermore, it is demonstrated that a power law electron energy distribution describes the time-variable observed fluxes better than a Maxwellian distribution.
منابع مشابه
Excitation of Alfvén waves by modulated HF heating of the ionosphere, with application to FAST observations
During the operation of the EISCAT high power facility (heater) at Tromsø, Norway, on 8 October 1998, the FAST spacecraft made electric field and particle observations in the inner magnetosphere at 0.39 Earth radii above the heated ionospheric region. Measurements of the direct current electric field clearly exhibit oscillations with a frequency close to the modulated frequency of heater (∼ 3 H...
متن کاملModel for artificial ionospheric duct formation due to HF heating
[1] Strong electron heating by the injection of highly powerfu l HF waves can lead to the format ion of ionospheric plasma density perturbations that stretch along the magnetic field lines. Those density perturbations can serve as ducts for guiding natural and artificial ELF/VLF waves. This paper presents a theoretical model of duct formation due to HF heating of the ionosphere. The model is ba...
متن کاملPositive storm effects in the dayside polar ionospheric F-region observed by EISCAT and ESR during the magnetic storm
EISCAT/ESR radar data and in situ FAST and POLAR satellite observations are coordinately analyzed to investigate positive ionospheric storm effects in the dayside upper F-region in both the polar cap and the auroral oval during the magnetic storm of 15 May 1997. An ionization enhancement, lasting for about 2.5 h, appeared first over the EISCAT site around magnetic noon; about one hour later, a ...
متن کاملThe response time of PMSE to ionospheric heating
[1] During July of 1999, experiments were conducted in northern Norway to investigate the effects of ionospheric heating on polar mesosphere summer echoes (PMSE). The experiments were conducted using the European incoherent scatter (EISCAT) VHF radar and heating facility. It was shown that heating can dramatically reduce the backscattered echo power of PMSE. Here, we reexamine the high temporal...
متن کاملComparison of temporal fluctuations in the total electron content estimates from EISCAT and GPS along the same line of sight
The impact of space weather events on satellitebased technologies (e.g. satellite navigation and precise positioning) is typically quantified on the basis of the total electron content (TEC) and temporal fluctuations associated with it. GNSS (global navigation satellite systems) TEC measurements are integrated over a long distance and thus may include contributions from different regions of the...
متن کامل