Project 3

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Project 3 Artificial Auroras
The Eurora
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Background The vast majority of observable matter
in the universe appears as plasma. Most
communication in the universe occurs via
electromagnetic waves. Our understanding of
wave-plasma interactions is incomplete. Heater
facilities and the ionosphere make a very good
plasma laboratory. Artificial optical emissions
provide direct evidence of electron acceleration
by wave-induced turbulent plasma processes. Since
1999, many new discoveries have been made.
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Some important highlights include 1) The
emission almost always appears close to the
magnetic field line direction.
Kosch et al., Geophys. Res. Lett., 27, 2817-2820,
2000.
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2) The optical emission almost always appears 10s
of km below the Langmuir and upper-hybrid
resonance height.
Kosch et al., Adv. Polar Upper Atmos. Res., 16,
1-12, 2002.
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3) Strong electron temperature enhancements occur
(up to 3000 K) with artificial auroras.
Gustavsson et al., J. Geophys. Res., 106,
29105-29123, 2001.
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4) Electron temperature enhancements are highly
aspect angle sensitive to the magnetic field line
direction. 5) Ion temperature enhancements of
500 K occur. 6) Artificial ion outflow occurs.
Rietveld, Kosch et al., J. Geophys. Res., 108,
1141, doi 10.1029/ 2002JA009543, 2003.
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7) Only O-mode pumping produces artificial
auroras. This is evidence that bulk electron
heating is not a mechanism.
Langmuir waves Upper-hybrid waves Electron bulk
heating
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8) Artificial auroras usually minimise when
pumping on a gyroharmonic, along with SuperDARN
backscatter power, indicating upper-hybrid wave
turbulence is the mechanism.
Kosch et al., Geophys. Res. Lett., 29(23),
2112-2115, 2002.
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9) For high pump powers, 9o S dip angle and 4th
gyro-harmonic pump frequency unstable auroral
rings form.
At pump on
60 s later
Kosch et al., Geophys. Res. Lett., 31, doi
10.1029/2004GL019713, 2004.
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10) The altitude of the rings is at/above the
pump wave reflection height.
Kosch et al., Geophys. Res. Lett., 31, doi
10.1029/2004GL019713, 2004.
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11) EISCAT data provides evidence for Langmuir
turbulence being the mechanism for auroral rings.
Kosch et al., Geophys. Res. Lett., 31, doi
10.1029/2004GL019713, 2004.
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Temperature modelling
Ashrafi, Kosch Honary, Adv. Space Res.,
manuscript in preparation
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Temperature modelling
For an assumed Maxwellian electron energy
distribution Modelled 630 nm ? 28
Rayleigh 557.7 nm ? 0.06 Rayleigh Observed 630
nm ? 300 Rayleigh 557.7 nm ? 125
Rayleigh Therefore artificial aurora comes from a
high non-Maxwellian plasma generated by
non-linear wave-plasma turbulence.
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Height triangulation

• Skibotn 50o field of view, zenith pointing
• Ramfjord 50o field of view, pointing 12o S
• Correct lens distortion using stars
• Convert images to right ascension and declination
• Convert images to azimuth and elevation
• Convert images to latitude and longitude for a
  selected altitude
• Compare images until best match to give altitude

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Height triangulation
Ashrafi, Kosch et al., Ann. Geophys., manuscript
in preparation
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• Platteville, Colorado
• SURA (Nizhni Novgorod), Russia
• Arecibo (Puerto Rico),
• Tromsø (Norway), HIPAS (Alaska)
• HAARP (Alaska)
• SPEAR (Svalbard)

World overview
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HAARP Pump cycle and frequency Reflection
altitude () and upper-hybrid resonance altitude
(?) Kodiak backscatter _at_ 10 MHz 630 557.7
nm calibrated photometer 5577/6300 steady-state
ratio
2nd gyro
3rd gyro
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The Future 1) Artificial aurora energy spectra ?
6300 (O1D) 2 eV ? 5577 (O1S) 4.5 eV ? 7774
(O) 9 eV ? 8446 (O) 11 eV ? 7320 (O)
19 eV ? 6400-6750 (N2 1NG) 9 eV ? 4278 (N2
1PG) 19 eV
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The Future 2) Neutral composition (N2/O)
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• The Future
• 2) Neutral composition (N2/O)
• Nitrogen vibrational states strongly absorb
  pump-accelerated electrons without producing a
  photon
• A) 9 eV 777.4 (O) and 640-675 (N2 1NG)
• B) 11 eV 844.6 (O) and 370-380 (N2 2PG)
• C) 557.7/630

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The Future 3) Langmuir (B-parallel) versus
upper- hybrid (B-perpendicular) turbulence i)
Langmuir waves UHF ESR ii) Upper hybrid waves
CUTLASS STARE plasma line
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The Future 3) CUTLASS STARE plasma line
Fscatter Fradar ? Fheater No orthogonality
required. No co-location of transmitter and
receiver required.
Hughes et al., Geophys. Res. Lett., doi
10.1029/2003GL018772, 2004
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The Future 4) In-situ measurement by dual rocket
through an artificial aurora over SPEAR i)
Off-gyroharmonic pumping ii) On-gyroharmonic
pumping Measure directly i) Electrostatic and
electromagnetic waves ii) Plasma irregularity
scale sizes iii) Plasma temperature iv) Photon
production rate v) Electron energy spectrum
(1-100 eV)
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The Future 4) Rocket shot
Kelley et al., J. Geophys. Res., 100,
17367-17376, 1995.