(A Project of the Jupiter Space Station)

III. Review of the Literature

The Solar Physics

The Sun dominates the solar system emission spectra from the viewpoint of an external observer looking at or listening to our world. During sunspot minima (quiet sun) the power of the solar emission ranges from 100 to 10000 watts per hertz. As of 1996 the Sun is in sunspot minima and will be moving to sunspot maxima which will occur during 2002. As solar activity increases (sunspots and solar flares) the power of the solar emission will increase 30 dB. The 1000 fold increase in power during sunspot maxima occurs primarily in the water-hole frequency range, i.e. 1200 - 1600 MHz (Kraus, 1986).

A solar flare with the help of the magnetic flux lines and with instantaneous, localized magnetic fields can produce a million megatons of TNT energy in a matter of minutes.

The sun's electromagnetic spectrum is a continuum of radiation spanning not only in the infrared, visible, and ultraviolet wavelengths, but also in the radio waves, X rays, and beyond. Sensors on the Earth and in space continuously observe specific portions of the solar energy spectrum to monitor these levels and give scientists indications of when significant events occur. Solar emissions in this category are all electromagnetic in nature, that is, they move at the speed of light. Events detected on the sun in these wavelengths begin to affect the Earth's environment approximately 8 minutes after they occur (Rosenthal, 1995).

The sun emits radio energy with a slowly varying intensity. This radio flux, which originates from atmospheric layers high in the sun's chromosphere and low in its corona, changes gradually from day-to-day, in response to the number of spot groups on the disk. Radio intensity levels consist of emission from three sources: from the undisturbed solar surface, from developing active regions, and from short-lived enhancements above the daily level. Solar flux density has been recorded routinely by radio telescopes since February 14, 1947 (Space Environment Center (SEC), 1996).

Until recently, most radiospectrographs spanned only a narrow range of wavelengths. Most radio bursts would exceed this range and therefore only the broad wavelength range into which they fell could be stated with certainty. Several new radiospectrographs (e.g. Culgoora in Australia and HIRAS in Japan) cover wide wavelength ranges. This makes it feasible and desirable to record the actual wavelength (or frequency) of each burst. The high resolution of some new instruments (such as GOES 10/12) also makes it possible to report more detailed and timely information about radio bursts (Space Environment Center (SEC), 1996).

"Solar activity is a measure of energy releases in the solar atmosphere, generally observed by X ray detectors on earth-orbiting satellites such as GOES 10. The X ray event classes correspond to a standardized method of classification based on the peak flux of the X ray emissions as measured by detectors. Solar X rays occupy a wide range of wavelengths with the portion used for flare classification from 0.1 nm through 0.8 nm. The classification scheme ranges in increasing X ray peak flux from B-class events, through C- and M-class, to X-class events at the highest end" (Rosenthal, 1995) (also see Appendix C, Glossary).

In addition to electromagnetic radiation, the sun constantly ejects matter in the form of atomic and subatomic particles. Consisting typically of electrons, protons, and helium nuclei, this tenuous gas is accelerated to speeds in excess of the gravitational escape velocity of the sun and thus moves outward into the solar system. The collective term for the gases and the particles making them up is the Solar Wind. The rotation of the sun is approximately a 27 day rotation period resulting in the clouds being slung outward in an expanding spiral pattern which (at the earth-sun distance) overtakes the earth from behind as it moves in orbit.

Kraus spells out the effects of different magnetic phenomena including plane waves in an ionized medium, magnetohydrodynamic waves (i.e. mhd waves or Alfven waves), and both magnetic mirror points and magnetic bottles. Plasma is frequently used as an example of a medium (Kraus, 1986). These wave premises are based on proofs and theories from 1930 to 1965 and from mainstream, established physics. The synchrotron mechanism for high energy electrons producing radio spectral emissions is a foundation for the SASER Project. Radio emissions have been produced in the laboratory (the General Electric Synchrotron) using weak magnetic fields which produce the lower frequencies in the radio spectrum.

We conclude from this that the Sun is a hotbed of wave generating laboratories which we plan to explore by attempting to mix weak microwave signals resulting in amplified, radio products which the SASER Project will attempt to detect on Earth.

The Solar Flare Model

The radio emission from a solar flare is broken into two phases and is illustrated in the model of Figure 2 taken from Wilde et al. The Phase 1 portion of the flare is relatively short lived, lasting only about 3 minutes. The short continuum emission of Type V can sometimes be detected. This phase is dominated by Type III emission moving rapidly from 400+ MHz to 20 MHz at about 100 MHz each minute. In small flares, Phase 1 may be all that is generated. If the flare is larger, then an accompanying Phase 2 begins which is characterized by slow drift bursts (Type II) that move from 400+ MHz to 20 MHz at the rate of 20 MHz per minute. The occasional development of an electron gas cloud with its own upper level shock front is interesting because this gas cloud radiates a continuum emission (Kraus, 1996).

The next Figure 3 represents a portrait of a strong, powerful solar flare over time. Whereas this figure shows a Type IV emission lasting around 15 minutes after the initial burst emissions, it is not uncommon to have this Type IV lasting up to 60 minutes or even much longer.

This theoretical model is both established and backed by modern data. Looking at Appendix B, page 1 of the SASER Database Report, The Merge of Radio Spectral Data to Flare Data by Spectral Class Type IV, one sees that even in sunspot minima there are X ray events which are precursors to flare events generating radio emissions. For example, our report shows a Type IV radio event occurring at 9:55 and ending 26 minutes later at 10:21. There is a corresponding flare event (with an M class X ray precursor) at 9:53. The complete data is produced from radio spectral data and flare data captured by Space Environment Center (SEC) observatories, NOAA, or the US Air Force (National Geophysical Data Center (NGDC), 1996). Our newly compiled SASER Database documents 22 such cases from July, 1994 to August, 1995.

The second SASER Database Report, Radio Spectral Data of Very Active Emissions with Spectral Class Type: IV, lists all the various emissions which occurred on days where there was at least two Type IV emissions. Both of these reports are followed and supported by an explanatory Legend which describes the columns within the reports. It should be apparent from reviewing these reports (found in Appendix B) that if we can be notified, within minutes, of an X ray early burst event that we can then bring our transmitting and receiving systems on-line and conduct this SASER experiment.

The Radio Waves

Why do we think that there might be natural mixing, amplification, and re-radiation of microwave signals beamed at the sun?

There exists precedence in nature for non-thermal radio emissions characterized by reflection, mixing, and amplification from high energy electron fluxes or flows. These are typically induced by strong magnetic fields (Jupiter) or the magneto-hydrodynamics of the Sun. Electrons moving at both high or relativistic speeds which are interfaced with microwave frequencies produce various synchrotronic emissions depending on whether the gyrating electrons are at the cyclotron or gyro frequency. These emissions are oscillating.

Natural frequency mixing producing subcarriers and harmonics is common in nature and can be produced artificially. High powered FM signals on Earth can even be reflected and diffracted to produce weaker AM signals with much of the modulated information in tact. Transconductance of two radio spectral frequencies can mix in a multiplicative fashion to create a third or fourth RF output signal. Because we will know one component of the product signal, we can recover our transmitted analog signal either directly or with spectral analysis software using Fast Fourier Transforms (FFT) of the signal and solar noise mixture.

The ARRL Handbook describes the phenomena of two signals combined in a wire or a circuit or even in the air as being a superposition and scaling where they become one combined signal. These combined signals may fashion themselves in the form of a summing amplifier or a modulated signal combination of a carrier frequency and an analog signal (ARRL, 1996). There could be a natural, evacuated cavity at the Sun that we will call Thunder Dome (see Figure 3) that has high energy electrons moving at near relativistic speeds. Both Thunder Dome or Pooch Hill (also seen in Figure 3) may provide us a natural mechanism to reach into and out of our Sun.

In 1979 A. O. Benz and H. R. Fitze attempted to mix a 2380 MHz radar signal (pulsed) with the solar coronal Langmuir waves... without detection. The radar was pulsed from .5 to 1.5 seconds using the Arecibo 300 meter. They believed that in 12 captures at least one source was in the beam. Their concept was to mix the microwave in a non-linear interaction to produce a radio signal to be Fourier analyzed for the transmitted signal pattern.

Like Benz and Fitze, in attempting to analyze the returned signal to Earth, we will use spectral DSP (digital signal processing) to search for our product signal in the noise. Referring to Figure 4, we illustrate using DSP a method to find the originating signal within a moon bounced reflection. In addition one can see an actual EME keyed transmission of a signal around 580 Hz. Unlike the expected SASER signal this signal is clearly above the noise.

Several other JSS experiments and papers dealing with pulling signal out of the noise are reported on the Jupiter Space Station web site at:

Figure 4 - SASER Radio Spectrum of Moon Bounced Signal

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