Low frequency waves during RF heating of the ionosphere: numerical simulations

A Surjalal Sharma, Xi Shao, Bengt Erik Eliasson, Dennis Papadopoulos

Research output: Contribution to conferenceAbstract

Abstract

Radio frequency heating of the ionosphere produces local plasma heating and the resulting pressure gradient leads to plasma currents. When the heating is modulated the time varying current can excite waves of frequency close to the modulation frequency and propagate away from the heating region. The generation of the waves by a modulated heating of the F-region ionosphere is modeled using numerical codes of wave propagation in the ionosphere with the conducting ground as the lower boundary and the magnetosphere as the top boundary. The diamagnetic current due to the pressure gradient resulting from the localized RF heating oscillates at the modulation frequency and excites hydromagnetic waves, mostly the magnetosonic mode. As these waves propagate away from the heated region in the F-region it encounters regions of different conductivity, driving an oscillating Hall current in the E-region where Hall conductivity is dominant. These currents produce shear Alfven waves which propagate along the field lines. Simulations of RF heating with modulation frequencies in the range 2 - 10 Hz in the high- and mid-latitude ionosphere provide the wave propagation characteristics which depend on the ionospheric conductivity, modulation frequency and size of the heated region. In the high-latitude case the wave propagation is simulated using an essentially vertical magnetic field and the parameters corresponding to the HAARP heater experiments are used. The measurements on the ground during these experiments agree well with the simulation results. The mid-latitude case is simulated using a code that uses a dipole magnetic field in polar coordinates. With a source located at L = 1.6 and altitude of 300 km the EMIC and whistler waves are generated and the field-aligned waves propagate to the conjugate region. The characteristics of these waves depend on the modulation frequency, and in the case of modulation at 10 Hz the EMIC waves encounter the resonance layer. The whistler waves on the other hand propagate along the field lines to the conjugate region. These simulations correspond to the ionospheric heating by the Arecibo facility.

Conference

ConferenceAGU Chapman Conference on Low-Frequency Waves in Space Plasmas
CountryKorea, Republic of
CityJeju Island
Period31/08/145/09/14

Fingerprint

ionospheres
low frequencies
heating
frequency modulation
simulation
wave propagation
F region
magnetohydrodynamic waves
pressure gradients
encounters
ionospheric heating
radio frequency heating
ionospheric conductivity
Hall currents
conductivity
polar coordinates
plasma heating
E region
plasma currents
heaters

Keywords

  • radio frequency heating
  • ionosphere
  • low frequency waves

Cite this

Sharma, A. S., Shao, X., Eliasson, B. E., & Papadopoulos, D. (2014). Low frequency waves during RF heating of the ionosphere: numerical simulations. Abstract from AGU Chapman Conference on Low-Frequency Waves in Space Plasmas, Jeju Island, Korea, Republic of.
Sharma, A Surjalal ; Shao, Xi ; Eliasson, Bengt Erik ; Papadopoulos, Dennis. / Low frequency waves during RF heating of the ionosphere : numerical simulations. Abstract from AGU Chapman Conference on Low-Frequency Waves in Space Plasmas, Jeju Island, Korea, Republic of.
@conference{7160e6dc2f984588b0f6026da8d61de0,
title = "Low frequency waves during RF heating of the ionosphere: numerical simulations",
abstract = "Radio frequency heating of the ionosphere produces local plasma heating and the resulting pressure gradient leads to plasma currents. When the heating is modulated the time varying current can excite waves of frequency close to the modulation frequency and propagate away from the heating region. The generation of the waves by a modulated heating of the F-region ionosphere is modeled using numerical codes of wave propagation in the ionosphere with the conducting ground as the lower boundary and the magnetosphere as the top boundary. The diamagnetic current due to the pressure gradient resulting from the localized RF heating oscillates at the modulation frequency and excites hydromagnetic waves, mostly the magnetosonic mode. As these waves propagate away from the heated region in the F-region it encounters regions of different conductivity, driving an oscillating Hall current in the E-region where Hall conductivity is dominant. These currents produce shear Alfven waves which propagate along the field lines. Simulations of RF heating with modulation frequencies in the range 2 - 10 Hz in the high- and mid-latitude ionosphere provide the wave propagation characteristics which depend on the ionospheric conductivity, modulation frequency and size of the heated region. In the high-latitude case the wave propagation is simulated using an essentially vertical magnetic field and the parameters corresponding to the HAARP heater experiments are used. The measurements on the ground during these experiments agree well with the simulation results. The mid-latitude case is simulated using a code that uses a dipole magnetic field in polar coordinates. With a source located at L = 1.6 and altitude of 300 km the EMIC and whistler waves are generated and the field-aligned waves propagate to the conjugate region. The characteristics of these waves depend on the modulation frequency, and in the case of modulation at 10 Hz the EMIC waves encounter the resonance layer. The whistler waves on the other hand propagate along the field lines to the conjugate region. These simulations correspond to the ionospheric heating by the Arecibo facility.",
keywords = "radio frequency heating, ionosphere, low frequency waves",
author = "Sharma, {A Surjalal} and Xi Shao and Eliasson, {Bengt Erik} and Dennis Papadopoulos",
year = "2014",
month = "9",
day = "5",
language = "English",
note = "AGU Chapman Conference on Low-Frequency Waves in Space Plasmas ; Conference date: 31-08-2014 Through 05-09-2014",

}

Sharma, AS, Shao, X, Eliasson, BE & Papadopoulos, D 2014, 'Low frequency waves during RF heating of the ionosphere: numerical simulations' AGU Chapman Conference on Low-Frequency Waves in Space Plasmas, Jeju Island, Korea, Republic of, 31/08/14 - 5/09/14, .

Low frequency waves during RF heating of the ionosphere : numerical simulations. / Sharma, A Surjalal; Shao, Xi; Eliasson, Bengt Erik; Papadopoulos, Dennis.

2014. Abstract from AGU Chapman Conference on Low-Frequency Waves in Space Plasmas, Jeju Island, Korea, Republic of.

Research output: Contribution to conferenceAbstract

TY - CONF

T1 - Low frequency waves during RF heating of the ionosphere

T2 - numerical simulations

AU - Sharma, A Surjalal

AU - Shao, Xi

AU - Eliasson, Bengt Erik

AU - Papadopoulos, Dennis

PY - 2014/9/5

Y1 - 2014/9/5

N2 - Radio frequency heating of the ionosphere produces local plasma heating and the resulting pressure gradient leads to plasma currents. When the heating is modulated the time varying current can excite waves of frequency close to the modulation frequency and propagate away from the heating region. The generation of the waves by a modulated heating of the F-region ionosphere is modeled using numerical codes of wave propagation in the ionosphere with the conducting ground as the lower boundary and the magnetosphere as the top boundary. The diamagnetic current due to the pressure gradient resulting from the localized RF heating oscillates at the modulation frequency and excites hydromagnetic waves, mostly the magnetosonic mode. As these waves propagate away from the heated region in the F-region it encounters regions of different conductivity, driving an oscillating Hall current in the E-region where Hall conductivity is dominant. These currents produce shear Alfven waves which propagate along the field lines. Simulations of RF heating with modulation frequencies in the range 2 - 10 Hz in the high- and mid-latitude ionosphere provide the wave propagation characteristics which depend on the ionospheric conductivity, modulation frequency and size of the heated region. In the high-latitude case the wave propagation is simulated using an essentially vertical magnetic field and the parameters corresponding to the HAARP heater experiments are used. The measurements on the ground during these experiments agree well with the simulation results. The mid-latitude case is simulated using a code that uses a dipole magnetic field in polar coordinates. With a source located at L = 1.6 and altitude of 300 km the EMIC and whistler waves are generated and the field-aligned waves propagate to the conjugate region. The characteristics of these waves depend on the modulation frequency, and in the case of modulation at 10 Hz the EMIC waves encounter the resonance layer. The whistler waves on the other hand propagate along the field lines to the conjugate region. These simulations correspond to the ionospheric heating by the Arecibo facility.

AB - Radio frequency heating of the ionosphere produces local plasma heating and the resulting pressure gradient leads to plasma currents. When the heating is modulated the time varying current can excite waves of frequency close to the modulation frequency and propagate away from the heating region. The generation of the waves by a modulated heating of the F-region ionosphere is modeled using numerical codes of wave propagation in the ionosphere with the conducting ground as the lower boundary and the magnetosphere as the top boundary. The diamagnetic current due to the pressure gradient resulting from the localized RF heating oscillates at the modulation frequency and excites hydromagnetic waves, mostly the magnetosonic mode. As these waves propagate away from the heated region in the F-region it encounters regions of different conductivity, driving an oscillating Hall current in the E-region where Hall conductivity is dominant. These currents produce shear Alfven waves which propagate along the field lines. Simulations of RF heating with modulation frequencies in the range 2 - 10 Hz in the high- and mid-latitude ionosphere provide the wave propagation characteristics which depend on the ionospheric conductivity, modulation frequency and size of the heated region. In the high-latitude case the wave propagation is simulated using an essentially vertical magnetic field and the parameters corresponding to the HAARP heater experiments are used. The measurements on the ground during these experiments agree well with the simulation results. The mid-latitude case is simulated using a code that uses a dipole magnetic field in polar coordinates. With a source located at L = 1.6 and altitude of 300 km the EMIC and whistler waves are generated and the field-aligned waves propagate to the conjugate region. The characteristics of these waves depend on the modulation frequency, and in the case of modulation at 10 Hz the EMIC waves encounter the resonance layer. The whistler waves on the other hand propagate along the field lines to the conjugate region. These simulations correspond to the ionospheric heating by the Arecibo facility.

KW - radio frequency heating

KW - ionosphere

KW - low frequency waves

UR - https://agu.confex.com/agu/14chapman/webprogram/Paper1610.html

UR - http://chapman.agu.org/spaceplasmas/

M3 - Abstract

ER -

Sharma AS, Shao X, Eliasson BE, Papadopoulos D. Low frequency waves during RF heating of the ionosphere: numerical simulations. 2014. Abstract from AGU Chapman Conference on Low-Frequency Waves in Space Plasmas, Jeju Island, Korea, Republic of.