Solar powered microwave transmission and interactions with atmopsheric plasmas

Abstract

We present (1) a proof of concept to operate solar powered microwave transmission, and (2) investigation of microwave interactions with atmospheric plasmas. In this conceptualized system, a solar thermophotovoltaic system is considered to produce direct current electricity, which is then converted to microwaves in an array. It has an intermediate structure between the solar cell and the sun. Computational analysis using the matrix transfer method of different materials at varying thicknesses will be used to analyze the absorption in the structure as well as to calculate the efficiency of the DC-AC conversion. The results from these simulations will provide insight on how to produce an economically and environmentally conscience energy source, that can be used for communication and remote sensing applications. However, it is expected that microwaves may interact with ionospheric plasmas, especially, in the E region to induce large scale fluctuations in plasma density and geomagnetic fields. This expectation arises from the facts that microwaves can impose nonlinear forces (i.e., ponderomotive force and thermal pressure force) on ionospheric plasmas. They subsequently produce a quasi-DC apparent electric field, acting on electrons to induce plasma density fluctuations (δn) according to electric Gauss law. Consequently, the apparent electric field together with the background Earth's magnetic field cause the so-called ExB electron drifts, and yield the geomagnetic field fluctuations (δB o ) according to Ampere's law. The simultaneous generation of dn and δB o is associated with a large-scale plasma instability driven by aforementioned nonlinear forces. Electron collisions play the following key roles in the determination of instability thresholds. (1) Electron collisions generate heat sources to excite the thermal instability. (2) Electron collisions impose damping on the excited dn and δB o . (3) Electron collisions reduce heat conduction loss. Judging from these facts, we can expect that microwave interactions can effectively start in ionospheric E region, where electrons have the largest collision rates due to dense neutral population density. The microwave-generated large scale δn and δB o can extend in a large range of altitude in the upper atmosphere. After we determine the instability thresholds, we can use them to set up the safe operation range of solar powered microwave transmission.