# Electron cyclotron harmonic resonances in high-frequency heating of the ionosphere

## Abstract

Electron acceleration by upper hybrid waves under cyclotron harmonic resonance interaction is studied. Theory is formulated; the analytical solutions in the second and fourth harmonic cyclotron resonance cases are obtained, and in the third harmonic case, a first order differential equation governing the evolution of the electron energy is derived. The theory is applied for explaining the generation of artificial ionization layers observed in high-frequency (HF) ionospheric heating experiments. The upper hybrid waves are assumed to be excited parametrically by the O-mode HF heating wave. As the decay mode is the lower hybrid wave, the excited upper hybrid waves have wavelengths ranging from 0.25 to 0.5 m, which are short enough to effectively incorporate the finite Larmour radius effect for the harmonic cyclotron resonance interactions as well as have a frequency bandwidth of about 20 kHz, which provides an altitude region of about 10 km for continuous harmonic cyclotron resonance interaction between electrons and descending waves in the slightly inhomogeneous geomagnetic field. The numerical results on electron acceleration show that electron fluxes with energies larger than 14 eV are generated in the three harmonic cases. These energetic electrons cause impact ionizations, which are descending to form artificial ionization layers atmore »

- Authors:

- Polytechnic Institute of New York University, 6 MetroTech Center, Brooklyn, New York 11201 (United States)

- Publication Date:

- OSTI Identifier:
- 22224194

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 9; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALTITUDE; ANALYTICAL SOLUTION; CYCLOTRON RESONANCE; DIFFERENTIAL EQUATIONS; ELECTROMAGNETIC RADIATION; EV RANGE; F REGION; GEOMAGNETIC FIELD; INTERACTIONS; KHZ RANGE; LAYERS; LOWER HYBRID CURRENT DRIVE; LOWER HYBRID HEATING; PLASMA WAVES; TAIL ELECTRONS

### Citation Formats

```
Kuo, Spencer P.
```*Electron cyclotron harmonic resonances in high-frequency heating of the ionosphere*. United States: N. p., 2013.
Web. doi:10.1063/1.4822336.

```
Kuo, Spencer P.
```*Electron cyclotron harmonic resonances in high-frequency heating of the ionosphere*. United States. doi:10.1063/1.4822336.

```
Kuo, Spencer P. Sun .
"Electron cyclotron harmonic resonances in high-frequency heating of the ionosphere". United States.
doi:10.1063/1.4822336.
```

```
@article{osti_22224194,
```

title = {Electron cyclotron harmonic resonances in high-frequency heating of the ionosphere},

author = {Kuo, Spencer P.},

abstractNote = {Electron acceleration by upper hybrid waves under cyclotron harmonic resonance interaction is studied. Theory is formulated; the analytical solutions in the second and fourth harmonic cyclotron resonance cases are obtained, and in the third harmonic case, a first order differential equation governing the evolution of the electron energy is derived. The theory is applied for explaining the generation of artificial ionization layers observed in high-frequency (HF) ionospheric heating experiments. The upper hybrid waves are assumed to be excited parametrically by the O-mode HF heating wave. As the decay mode is the lower hybrid wave, the excited upper hybrid waves have wavelengths ranging from 0.25 to 0.5 m, which are short enough to effectively incorporate the finite Larmour radius effect for the harmonic cyclotron resonance interactions as well as have a frequency bandwidth of about 20 kHz, which provides an altitude region of about 10 km for continuous harmonic cyclotron resonance interaction between electrons and descending waves in the slightly inhomogeneous geomagnetic field. The numerical results on electron acceleration show that electron fluxes with energies larger than 14 eV are generated in the three harmonic cases. These energetic electrons cause impact ionizations, which are descending to form artificial ionization layers at the bottom of the ionospheric F region.},

doi = {10.1063/1.4822336},

journal = {Physics of Plasmas},

number = 9,

volume = 20,

place = {United States},

year = {Sun Sep 15 00:00:00 EDT 2013},

month = {Sun Sep 15 00:00:00 EDT 2013}

}