Ionospheric Modification at Twice the Electron Cyclotron Frequency

F. T. Djuth, T. R. Pedersen, E. A. Gerken, P. A. Bernhardt, C. A. Selcher, W. A. Bristow, and M. J. Kosch

Phys. Rev. Lett. 94, 125001 – Published 31 March 2005

Abstract

In 2004, a new transmission band was added to the HAARP high-frequency ionospheric modification facility that encompasses the second electron cyclotron harmonic at altitudes between $\sim 220$ and 330 km. Initial observations indicate that greatly enhanced airglow occurs whenever the transmission frequency approximately matches the second electron cyclotron harmonic at the height of the upper hybrid resonance. This is the reverse of what happens at higher electron cyclotron harmonics. The measured optical emissions confirm the presence of accelerated electrons in the plasma.

Received 22 November 2004

DOI:https://doi.org/10.1103/PhysRevLett.94.125001

Authors & Affiliations

F. T. Djuth¹, T. R. Pedersen², E. A. Gerken³, P. A. Bernhardt⁴, C. A. Selcher⁵, W. A. Bristow⁶, and M. J. Kosch⁷

¹Geospace Research, Inc., El Segundo, California 90245, USA
²Air Force Research Laboratory, Hanscom Air Force Base, Massachusetts 01731, USA
³Electrical and Computer Engineering Department, Cornell University, Ithaca, New York 14853, USA
⁴Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, USA
⁵Information Technology Division, Naval Research Laboratory, Washington, D.C. 20375, USA
⁶Geophysical Institute, UAF, Fairbanks, Alaska 99775, USA
⁷Communications Systems, Lancaster University, Lancaster LA1 4YR, United Kingdom

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Vol. 94, Iss. 12 — 1 April 2005

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