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New ELF/VLF Wave Injection Facility. Motivation: increased scientific interest in wave-particle interactions and their global role in the acceleration and loss of energetic particles

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new elf vlf wave injection facility
New ELF/VLF Wave Injection Facility
  • Motivation: increased scientific interest in wave-particle interactions and their global role in the acceleration and loss of energetic particles
  • Active experiments allow us to quantify these complex non-linear interactions in way that passive observations or numerical modeling do not.
  • New facility would be open for experiments to be conducted by independent investigators
  • Suites of supporting instrumentation at the site, in the conjugate region, and arrays of low-power instruments at distances away from the site
electron precipitation
Electron Precipitation
  • Clear evidence of electron precipitation induced by Siple was not found.
  • Siple frequencies were likely too high
  • Detection instruments were not as developed
  • inside plasmapause, 3-5 kHz waves resonate with few keV electrons
  • Radiating at lower frequencies would be a major improvement
  • inside plasmapause, 500 Hz waves resonate with 10’s of keV electrons

Dots are measured duct

parameters from Siple

observing precipitation
Observing Precipitation
  • Significant advances in instrumentation increase the ability to measure low levels of electron precipitation
  • Optical instruments, photometers and imagers
  • Imaging riometers
  • Subionospheric VLF remote sensing
  • X-rays
  • Ground based / Balloon / Rocket / Spacecraft
ulf vlf interactions
ULF/VLF Interactions

The transmission format at Siple was limited

The new facility would investigate the generation of ULF waves by amplitude modulated transmission at VLF frequencies.

  • Generate ULF micropulsations (0.1 sec to 10 min period)
  • Detect with arrays of LPM

[Bell, 1976]

facility location
Facility Location
  • > 2000 m ice thickness
  • Proximity to the plasmapause, L=4-5
  • Easy access to the northern hemisphere conjugate region
  • Excitation of wave-particle interactions involving > 40 keV electrons (freq as low as 500 Hz)
  • Effective radiated power of 10-50 kW
ice thickness
Ice Thickness

Ice thickness is critical in determining radiation efficiency


antenna configurations
Antenna Configurations

For operation at

500 Hz, l = 200 km

siple station antarctica vlf wave injection experiment
Siple Station, Antarctica VLF Wave-injection Experiment
  • NSF-funded Stanford experiment (1973-88)
  • VLF waves (~2-6 kHz) injected from Siple Station, Antarctica
  • 150 kW transmitter, 42-km antennas
  • Tuned with large capacitors and coils
  • VLF receiver at Roberval & Lake Mistissini, Quebec
  • Controlled studies of cyclotron resonant wave-particle interactions
  • Uncovered many aspects of wave growth & emission triggering