The proposed work is a three year effort to establish and operate a very low frequency (VLF) beacon transmitter at South Pole, for the continuous measurement of solar effects on the Earth's mesosphere and lower ionosphere. Specifically the transmitter will produce data on solar proton events, relativistic (>300 keV) electron precipitation from the Earth's outer radiation belts, and energetic electron precipitation and Joule heating components of high latitude/polar cap magnetosphere-ionosphere coupling processes. The relativistic electron population as measured at geosynchronous orbit exhibits pronounced fluctuations in association with substorm and solar activity. During an event, these highly energetic electrons can penetrate to altitudes as low as 30-40 km, producing ionization, x-rays and possibly affecting chemical reactions involving ozone production. The extent of relativistic electron precipitation will be observed by means of amplitude and phase variations of the South Pole VLF signal as received at various Antarctic stations. The South Pole beacon will synergistically enhance other antarctic upper atmospheric research efforts, such as the Automatic Geophysical Observatory programs and the southern hemisphere coherent HF radar network (SUPERDARN). The proposed program also strongly complements ongoing satellite based measurements of trapped and precipitating high energy electrons both at low altitudes (SAMPEX) and high altitudes (POLAR). The beacon will transmit at approximately 20 kHz, radiating 1 kW of total power with a ~6.25 km (tip-to-tip length) long horizontal dipole antenna. It will be operating under computer control with a synoptic schedule of about 1 min out of every 15 minutes. ***
