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Wave Injection at Low Latitudes

Wave Injection at Low Latitudes. Mark Go lkowski Remediation of Enhanced Radiation Belts Workshop Lake Arrowhead, CA March 3-6, 2007. Adelaide, Australia. ~500 kW ? Navigation transmitter in Komsomolsk na Amur in Russian far east (400 msec pulses) at L = 2

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Wave Injection at Low Latitudes

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  1. Wave Injection at Low Latitudes Mark Golkowski Remediation of Enhanced Radiation Belts Workshop Lake Arrowhead, CA March 3-6, 2007

  2. Adelaide, Australia • ~500 kW ? Navigation transmitter in Komsomolsk na Amur in Russian far east (400 msec pulses) at L = 2 • Conjugate point in southern Australia • Stanford University receiver since January 2007 • Explore and quantify wave-growth Stanford Scientists Kangaroos

  3. Russian Alpha Transmitters • 3.6 second pattern (six 0.6s segments) • 400ms pulses, 200ms off between pulses • Three sites alternate among 3 frequencies 14.88 kHz

  4. Historical Background • Triggered emissions have been observed from other mid-latitude transmitters: NAA (L=2) 14.5 kHz, 200 msec pulses • Whistler-mode Komsomolsk Alpha pulses have been studied by Tanaka et al. 1987 in the context of whistler propagation characteristics

  5. Example 1-Hop

  6. Temporal (non-linear) Growth

  7. Example Growth ~7-8 dB total ~70-80 dB/sec

  8. Example Growth

  9. Example Detection

  10. 10-Day Statistics (1-10 April) • Count of 1-hop observations in synoptic (1min/5min) recordings • 10 days during and after a geomagnetic disturbance • 1-Hop observations show qualitative relationship to geomagnetic activity Need more data to quantify relationship

  11. Diurnal patterns Day Night Day Day Night Day

  12. Average Daily Variations Tanaka et al. 1987 Stanford 2008 Sunset Sunrise • Diurnal variation shows maxima after sunset and sunrise • Tanaka et al. 1987: diurnal variation is same for whistlers and is a propagation effect (duct formation, coupling in/out of duct)

  13. Summary • 1-Hop echoes regularly observed from Komsomolsk Alpha transmitter • Echoes exhibit temporal growth of ~70-80 dB/sec • Propagation delays of 460 msec – 540msec equatorial electron concentrations of 4000-5000 cm-3 at L = 2 • Triggered of frequency emmisions not observed yet, except perhaps on DEMETER satellite • Diurnal variations likely result from propagation/ducting effects • Future Work: statistically quantify effect of geomagnetic conditions on wave growth

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