Auroral dynamics EISCAT Svalbard Radar: field-aligned beam  complicated spatial...

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Transcript of Auroral dynamics EISCAT Svalbard Radar: field-aligned beam  complicated spatial...

  • Slide 1
  • Auroral dynamics EISCAT Svalbard Radar: field-aligned beam complicated spatial structure (
  • In the ionosphere: size of radar field of view large and variable horizontal velocities (> 2 km/s) filamentary parallel currents (> 50 A/m 2 )
  • Slide 16
  • upward In the ionosphere: after 4.5 s Maximum of precipitating energy (ie auroral emission) is not coincident with field-aligned current layer.
  • Slide 17
  • Ionospheric precipitation energy simulated auroral image
  • Slide 18
  • How to generate large velocities 100 nT + average plasma density (1-2 km/s) 400 nT or low density plasma (4-8 km/s) only very fast time variation can generate high speed flows
  • Slide 19
  • To image aurora in the magnetic zenith in forbidden ion line and directly observe plasma drifts, with sub-km and sub-sec resolution. Concurrent imaging in other lines characterises the production of the metastable ions. 3. The ASK concept ASK stands for the Auroral Structure and Kinetics So....
  • Slide 20
  • Physics summary how to generate auroral structure- top to bottom structure and processes at magnetospheric boundaries solar wind dynamic pressure changes, magnetic reconnection, Kelvin Helmholtz instabilities, diffusion by micro turbulence physical mechanism for transport of information field-aligned currents and Alfvn waves, fast waves or beams of particles field-aligned currents magnetic field geometry altered If processes lead to a violation of frozen-in condition magnetic field lines have no identity transport of information not linear physical processes in the inner magnetosphere could alter the magnetic topology, violate the frozen-in condition and generate structures in addition to those of the source at the magnetospheric boundary effect of ionosphere changes in ionospheric conductivity from particle precipitation will have a significant influence on magnetosphere-ionosphere coupling