Wave injection at low latitudes
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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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Wave injection at low latitudes

Wave Injection at Low Latitudes

Mark Golkowski

Remediation of Enhanced Radiation Belts Workshop

Lake Arrowhead, CA

March 3-6, 2007


Adelaide australia

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


Russian alpha transmitters

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


Historical background

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


Example 1 hop

Example 1-Hop


Temporal non linear growth

Temporal (non-linear) Growth


Example growth

Example Growth

~7-8 dB total

~70-80 dB/sec


Example growth1

Example Growth


Example detection

Example Detection


10 d ay s tatistics 1 10 april

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


Diurnal patterns

Diurnal patterns

Day

Night

Day

Day

Night

Day


Average daily variations

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)


Summary

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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