Utilizing nonlinear ELF generation in modulated ionospheric heating experiments for communications applications
Article first published online: 28 FEB 2013
©2013. American Geophysical Union. All Rights Reserved.
Volume 48, Issue 1, pages 61–68, January/February 2013
How to Cite
2013), Utilizing nonlinear ELF generation in modulated ionospheric heating experiments for communications applications, Radio Sci., 48, 61–68, doi:10.1002/rds.20014., , , and (
- Issue published online: 12 APR 2013
- Article first published online: 28 FEB 2013
- Accepted manuscript online: 19 JAN 2013 12:52PM EST
- Manuscript Accepted: 9 JAN 2013
- Manuscript Revised: 3 DEC 2012
- Manuscript Received: 29 SEP 2012
- HAARP, Office of Naval Research, Air Force Research Laboratory, and Defense Advanced Projects Research Agency. Grant Numbers: N0001405C0308, N00014091
- modulated heating;
 Modulated high-frequency heating of the D region ionosphere near the auroral electrojet can generate extremely low frequency (ELF; 3 Hz–3 kHz) radio waves. The modulated heating process is nonlinear and generates harmonics at integer multiples of the ELF modulation frequency. Quaternary phase shift keying, a digital modulation technique is applied to ELF waves to demonstrate transmission of digital data. Data were successfully decoded at a nearby receiver and the bit error rate computed. Square wave modulation of the high-frequency heater results in stronger signals and hence a smaller bit error rate. Simulations of the communication system using ELF waveforms and noise signals derived from ELF observations are also conducted. These simulations show that using higher harmonics of the ELF signal to improve the signal-to-noise ratio can reduce the bit error rate, although only when these harmonics are below ~4.5 kHz because of radio atmospherics (sferics) generating strong impulsive noise at higher frequencies.