Astrophysics/Space Physics Seminar
Dr. William S. Kurth; Department of Physics and Astronomy; University of Iowa
“Juno Observations of Plasma Waves Related to Jovian Ionospheric Plasma Densities”
Abstract: In its highly eccentric polar orbit of Jupiter, Juno passes within a few thousand kilometers of Jupiter’s 1-bar level, allowing in situ observations of the giant planet’s ionosphere for the first time. The Waves investigation on Juno measures radio and plasma waves in the frequency range of 50 Hz to 40 MHz and has detected spectral features related to the electron plasma frequency during each perijove. These features include electron plasma oscillations and the upper frequency extent of whistler mode hiss, both occurring at or near the electron plasma frequency in Jupiter’s strong magnetic field. The square of the electron plasma frequency is related to the electron density. Preliminary peak plasma densities observed lie in the range of 50 – 5000 cm-3, depending on altitude and perhaps latitude. We discuss these indicators of plasma density and some lingering questions of interpretation.