Early Experiments at the Arecibo Observatory---Cross Modulation for Measuring D-Region Electron Densities Generation of ELF/VLF Signals by Modulating the Dynamo Current System

Authors: A. J. Ferraro

Source: FERMAT, Volume 02, Communication 3, Mar_Apr, 2014

Abstract: This paper briefly summarizes the research that the Penn State University team has accomplished using the heating facilities of the Arecibo Observatory. Heating experiments covered two broad areas. One using the cross modulation experiment (also known as the Luxembourg effect) to measure D-region electron densities . Originally done at the PSU heating facility and then moved to the Arecibo facilities. The other area was involved in modulation the dynamo current system in order to generate ELF/VLF signals useful for submarine communications.

The former data was used to support in the understanding of the physics and chemistry for the formation of the D-region. Earlier results at Arecibo attempted to compare those results with the incoherent scatter measurements of low-lying ionization.

The generation and measurements of the ELF/VLF signals were made at close, then moderate then much longer paths. These will be discussed.

An important part of our program was in the design of the final heating antenna at Islote. The author, Breakall and LaLonde were instrumental with this design. Prior to that antenna, a HF log periodic antenna was placed above the dish and measurements proceeded for a few years in that mode until the completion of the Islote antenna array. Due to a loss of the Islote array in a hurricane, HF heating was at a standstill but a new antenna design by Breakall will again place an improved array above the dish to allow future heating experiments. The modulation of the dynamo current system led to conducting the experiment using other current systems like the equatorial electrojet and the polar electrojet. Arecibo provided a rich environment for the PSU researchers to continue their efforts. We thank Arecibo for the great support from all that was given to us.

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Early Experiments at the Arecibo Observatory