Aeronomy and Astrophysics

The polar regions have been called Earth's window to outer space. This term originally applied to study of aurora and other phenomena related to interaction of solar plasmas and fields. In this context the polar upper atmosphere is a screen on which the results of such interactions can be viewed and through which other evidence of space physics processes can pass. Today, this concept of Earth's polar atmosphere as a window includes research in other fields as well. With discovery of polar stratospheric ozone depletions, a window previously thought “closed” (the ultraviolet window) is now known to “open” in certain seasons. In astronomy and astrophysics, favorable atmospheric conditions and the unique location of the South Pole enable scientists to use this window to probe the structure of the Sun and the universe with unprecedented precision.

The aeronomy and astrophysics program supports studies of three regions:

• the stratosphere and the mesosphere. Current research focuses on stratospheric chemistry and aerosols, particularly in the context of the ozone hole. The polar stratosphere is expected to be a field of continued interest and growth.
• the thermosphere, the ionosphere, and the magnetosphere. These regions derive many of their characteristics from the interplay of ionized plasmas and energetic charged particles with geomagnetic and geoelectric fields. The upper atmosphere, particularly the ionospheric portion of it, is the ultimate sink of solar wind energy that is transported into the magnetosphere. Energy dissipates in the ionosphere because of particle precipitation, which is the result in part of resonant wave-particle interactions, and because of the Joule heating that is a result of currents driven by electric fields.
• astronomy and astrophysical studies of the regions of the universe outside the magnetosphere, including solar astronomy and cosmic ray physics. Astrophysical studies are primarily conducted at the South Pole station or on long-duration balloon flights launched from McMurdo.

Major goals are to sponsor research that requires or would benefit from the unique conditions of the Antarctic, to contribute to understanding of the role of the Antarctic in global environmental change, to participate in interdisciplinary studies of geosphere-biosphere interactions in the middle and upper atmosphere, and to improve understanding of the coupling of the Earth's polar atmosphere with the magnetosphere and of the ways in which both are affected by solar activity.

As an example of the unique conditions which can be exploited for science, AMANDA, which is pictured above, uses photo detectors buried over a kilometer deep in the ice sheet at south pole to detect high energy neutrinos which can be used to image portions of the Universe which are completely obscured to ordinary radiation.