Last year was The High-frequency Active Auroral Research Program (HAARP) has a history of some very entertaining theories about its purpose. Its been reported as being responsible for making caribou walk backwards, for knocking satellites out of the sky, and even for causing Hurricane Katrina. While the truth isn’t quite so spectacular, it is still quite interesting and includes some excellent research.

HAARP was built and operated by the Air Force, Navy, and DARPA, who were forced to discontinue their research program when sequestration resulted in large cuts to their budgets. Through a long a circuitous road, the GI now owns the HAARP facilities and is seeking support for its operation. Since we own it, it’s time we started thinking about what to do with it. Toward that end, this talk is an introduction to high-frequency (HF) ionospheric modification. HAARP is what is colloquially known as an ionospheric heater. HF heating is a phenomenon that was first observed in the 1930’s in cross-modulation of radio signals (Luxembourg effect). Since then it has developed into a distinct sub-discipline of plasma physics. This talk will give some historical background on heating and of HAARP, then will describe the physics of the interaction between HF electromagnetic waves with plasmas. It will end with some results of HF heating research, and some comments about the future of HAARP.