Spring 2006 Issue

Ionospheric Phenomena
on Other Planets

Information obtained recently by various space probes points out
ionospheric phenomena on other planets similar to those found in
Earth’s E-region. Further exploration in this area would help expand
our knowledge of terrestrial modes of VHF propagation on Earth. WB2AMU explains . . .

By Ken Neubeck, WB2AMU

The saying “we are not alone” has often been used in the past to describe the UFO phenomenon. In a way, this phrase is also appropriate to describe the various ionospheric phenomena that result in the different radio propagation modes that we experience on the planet Earth, in particular those which occur in the E-region of the ionosphere. Sporadic-E propagation is one such propagation mode, and it occurs in force during the respective summer months of the Northern and Southern Hemispheres on the 6-meter band, where signals are efficiently reflected off ion layers in the E-region. Another E-region phenomenon is the mysterious aurora mode, where radio signals are reflected off the active aurora in a backscatter mode and have tremendous distortion. Radio amateurs get to experience these really interesting modes by operating on the VHF bands at the right time.
It is so easy for hams to think that aurora conditions and sporadic-E propagation are unique only to Earth. However, as recent results obtained by various space probes have pointed out, it is apparent that many of the other planets in our solar system have similar physical phenomena. These include the aurora phenomenon as well as the existence of metallic-ion layers in the atmosphere.

Such an area of exploration would be extremely helpful in increasing our knowledge base of terrestrial modes of VHF propagation on Earth, such as aurora and sporadic-E. While other planets have noticeable differences in the reasons why these phenomena occur, the understanding of these differences and why they exist will ultimately lead to a clearer understanding of the behavior of aurora and sporadic-E propagation modes on Earth.

In this article we will concentrate on the above two E-region propagation modes on Earth and explore the form in which they exist on other planets in our solar system. The formal, structured ionosphere that exists on Earth—where there is a clear distinction between layers (known as the D, E, and F region)—may or may not exist in a similar manner on other planets. Although the presence of a metallic-ion layer (which is what sporadic-E is on Earth) and an aurora-type phenomenon has been noted in the ionosphere of other planets, at this time no determination of different layers has been made.


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