Abstract
(SLT) and associated electron acceleration at different angles of incidence of ordinary (O) mode pump waves. For angles of incidence within the Spitze cone, the turbulence initially develops within the first maximum of the Airy pattern near the plasma resonance altitude. After a few milliseconds, the turbulent layer shifts downwards by about 1 km. For injections outside the Spitze region, the turning point of the pump wave is at lower altitudes. Yet, an Airy-like pattern forms here, and the turbulence development is quite similar to that for injections within the Spitze. SLT leads to the acceleration of 10–20 eV electrons that ionize the neutral gas thereby creating artificial ionospheric layers. Our numerical modeling shows that most efficient electron acceleration and ionization occur at angles between the magnetic and geographic zenith, where SLT dominates over weak turbulence. Possible effects of the focusing of the electromagnetic beam on magnetic field-aligned density irregularities and the finite heating beam width at the magnetic zenith are also discussed. The results have relevance to ionospheric heating experiments using ground-based, high-power radio transmitters to heat the overhead plasma, where recent observations of artificial ionization layers have been made.
| Language | English |
|---|---|
| Article number | 415810201 |
| Number of pages | 16 |
| Journal | Journal of Plasma Physics |
| Volume | 81 |
| Issue number | 02 |
| Early online date | 6 Nov 2014 |
| DOIs | |
| Publication status | Published - Apr 2015 |
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Keywords
- ionospheric turbulence
- strong Langmuir turbulence
- electron acceleration
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Incidence angle dependence of Langmuir turbulence and artificial ionospheric layers driven by high-power HF-heating. / Eliasson, B.; Milikh, G.; Shao, X.; Mishin, E. V.; Papadopoulos, K.
In: Journal of Plasma Physics, Vol. 81, No. 02, 415810201, 04.2015.Research output: Contribution to journal › Article
TY - JOUR
T1 - Incidence angle dependence of Langmuir turbulence and artificial ionospheric layers driven by high-power HF-heating
AU - Eliasson, B.
AU - Milikh, G.
AU - Shao, X.
AU - Mishin, E. V.
AU - Papadopoulos, K.
N1 - © Cambridge University Press 2015
PY - 2015/4
Y1 - 2015/4
N2 - We have numerically investigated the development of strong Langmuir turbulence(SLT) and associated electron acceleration at different angles of incidence of ordinary (O) mode pump waves. For angles of incidence within the Spitze cone, the turbulence initially develops within the first maximum of the Airy pattern near the plasma resonance altitude. After a few milliseconds, the turbulent layer shifts downwards by about 1 km. For injections outside the Spitze region, the turning point of the pump wave is at lower altitudes. Yet, an Airy-like pattern forms here, and the turbulence development is quite similar to that for injections within the Spitze. SLT leads to the acceleration of 10–20 eV electrons that ionize the neutral gas thereby creating artificial ionospheric layers. Our numerical modeling shows that most efficient electron acceleration and ionization occur at angles between the magnetic and geographic zenith, where SLT dominates over weak turbulence. Possible effects of the focusing of the electromagnetic beam on magnetic field-aligned density irregularities and the finite heating beam width at the magnetic zenith are also discussed. The results have relevance to ionospheric heating experiments using ground-based, high-power radio transmitters to heat the overhead plasma, where recent observations of artificial ionization layers have been made.
AB - We have numerically investigated the development of strong Langmuir turbulence(SLT) and associated electron acceleration at different angles of incidence of ordinary (O) mode pump waves. For angles of incidence within the Spitze cone, the turbulence initially develops within the first maximum of the Airy pattern near the plasma resonance altitude. After a few milliseconds, the turbulent layer shifts downwards by about 1 km. For injections outside the Spitze region, the turning point of the pump wave is at lower altitudes. Yet, an Airy-like pattern forms here, and the turbulence development is quite similar to that for injections within the Spitze. SLT leads to the acceleration of 10–20 eV electrons that ionize the neutral gas thereby creating artificial ionospheric layers. Our numerical modeling shows that most efficient electron acceleration and ionization occur at angles between the magnetic and geographic zenith, where SLT dominates over weak turbulence. Possible effects of the focusing of the electromagnetic beam on magnetic field-aligned density irregularities and the finite heating beam width at the magnetic zenith are also discussed. The results have relevance to ionospheric heating experiments using ground-based, high-power radio transmitters to heat the overhead plasma, where recent observations of artificial ionization layers have been made.
KW - ionospheric turbulence
KW - strong Langmuir turbulence
KW - electron acceleration
UR - http://journals.cambridge.org/action/displayJournal?jid=PLA
U2 - 10.1017/S0022377814000968
DO - 10.1017/S0022377814000968
M3 - Article
VL - 81
JO - Journal of Plasma Physics
T2 - Journal of Plasma Physics
JF - Journal of Plasma Physics
SN - 0022-3778
IS - 02
M1 - 415810201
ER -