Main task  Investigate radio emissions of magnetospheric and atmospheric processes with ground- and space-based radio antennas including calibration of the antenna systems Main research topics 1.Calibration of antennas on spacecraft by numerical simulations, rheometry, anechoic chamber measurements, and in-flight 2.Radiophysics of magnetized planets and the Sun: Solar radio emissions, Auroral kilometric radiation (AKR) at Earth, Jovian hectometric (HOM) and decametric (DAM) emission, Saturn kilometric radiation (SKR) and narrowband emissions 3.Radio emissions from lightning on planets with focus on Saturn Refereed publications (since Jan 2013)  Total: 12 (first author: 2) Educational activities (since Jan 2013)  1 completed master thesis  1 ongoing doctoral thesis Radio Waves IWF/ÖAW1

Lead: Georg Fischer  Staff: M. Boudjada, M. Kapper (50%), J. Pagaran, M. Panchenko, (M. Sampl left, H.O. Rucker retired)  Students: PhD: C. Weber; Master: G. Rief (thesis completed) Cooperation within IWF  Exoplanetary radio emissions (Lammer et al., Khodachenko et al.)  Auroral and magnetospheric processes (Nakamura et al.)  Instrument developers (Steller et al.), Solar Orbiter RPW Key external collaboration USA: Dept. of Physics & Astronomy/Univ. of Iowa, Caltech Pasadena, Hampton Univ., NASA-GSFC; France: LESIA Meudon, LATMOS CNRS Guyancourt; Germany: Univ. Dresden, Astrophysical Inst. Potsdam; Ukraine: Inst. for Radio Astronomy; Russia: Inst. of Applied Physics/RAS; Sweden: Swedish Inst. of Space Physics Who are we? IWF/ÖAW2

3 Anechoic Chamber Measurements  Solar Orbiter hardware model 1:50 for anechoic chamber measurements of RPW antenna system  Measurements of antenna pattern from 8-20 MHz ( MHz in chamber) and antenna S-parameters  Construction of a corresponding pre-amplifier for model  Numerical computer simulations with FEKO to gain surface currents on patch model, calculate antenna parameters (effective lengths, impedances), modeling of antenna heating circuit & influence of radii, comparison with anechoic chamber results  Solar Orbiter launch planned for Jan 2017

In-flight Calibration of STEREO/WAVES IWF/ÖAW4  Effective length vectors were determined using the terrestrial AKR observed in early stage of STEREO mission during roll maneuvers  Least squares method combined with a genetic algorithm was applied to fit the best physical model to the observations  Accurate results confirm the results of rheometry (experimental method with model in electrolytic tank) and numerical wire-grid simulation  Our effective length vectors are recommended as a basis for future evaluation of SWAVES data (direction-finding & polarization) STEREO configuration (upper left), dynamic spectra of AKR recorded by STEREO-B during roll maneuvers (lower left) and modeled signals (red lines) compared to observations (right) [Panchenko et al., 2014]

Periodic bursts of non-Io DAM:  Period ~10.07 h (~1.5% longer than Jupiter System III rotation)  Correlation with solar wind  Possible origin: interchange instability in the Io plasma torus triggered by solar wind pulses Investigation of Io plasma torus:  Occultation of hectometric emission  Radio remote sensing of Io plasma ribbon & estimation of electron density  Study of local time dependence IWF/ÖAW5 Jovian Radio Emissions STEREO Waves and Cassini RPWS spectra of Jovian periodic bursts [Panchenko et al., 2013]

IWF/ÖAW6 Ground-Based Radio Observations Detection of periodic Jovian bursts from the ground  Simultaneous long lasting observations using STEREO/WAVES and the ground-based radio telescope URAN-2 (Poltava, Ukraine)  Non-Io DAM periodic bursts observed up to 25 MHz with resolution of fine structures  Bursts observed with LH & RH circular polarization components from both hemispheres Detection of Saturn lightning from the ground  First ground-based detection of Saturn lightning with UTR-2 radio telescope (ON-OFF beams)  Good agreement with Cassini/RPWS lightning observations despite radio interferences  High temporal resolution observations indicate similar structures of Saturn lightning to terrestrial intracloud lightning [Konovalenko et al., 2013]

IWF/ÖAW7 Evolution of the Great White Spot  GWS (Great White Spot) is a large scale disturbance in Saturn’s atmosphere (a giant thunderstorm, where we detect lightning radio emissions with the Cassini RPWS instrument)  Lightning flashes detected from 5 Dec to 28 Aug  Five GWS events in history: 1876, 1903, 1933, 1960, 1990  GWS consists of head (~10,000 km in latitude, lightning activity with rate ~10 s -1 ), and tail (300,000 km around Saturn)  Head spawned anticyclonic vortices and flashes were optically observed in blue light on dayside (in cyclonic gaps)  Large anticyclonic vortex (AV) collided with head in mid-June 2011 leading to decrease in flash rate and final demise  Total lightning power: W, Storm total power: W [Dyudina et al., 2013]

Future Plans: IWF/ÖAW8 Antenna calibration  Antenna optimization studies for RPWI of JUICE  Solar Orbiter antenna calibration with rheometry Solar & planetary radio emissions  Stereoscopic space- and ground-based observations of Jovian DAM and Solar radio emissions (Stereo WAVES, Juno, Solar Orbiter)  Ground-based radio observations (UTR-2, NenuFAR, LOFAR) with search for exoplanetary radio emissions  Long-term behavior of Saturn kilometric radiation and narrowband radio emissions (Cassini RPWS) Lightning radio emissions  Continued analysis of Saturn lightning  Radio Wave Group has Co-I ships of Cassini/RPWS, Stereo WAVES, Solar Orbiter RPW and JUICE RPWI (data access)

Thank you IWF/ÖAW9

Dr. Georg Fischer Career Summary Scientist, Institut für Weltraumforschung, ÖAW, Austria 2004PhD, University of Graz, Austria Postdoc, Department of Physics and Astronomy, University of Iowa, USA since 2008Senior Scientist, Institut für Weltraumforschung, ÖAW, Austria Publications 58 Articles (First Author: 19, Refereed Articles: 34) Research Interests  Lightning on planets (mainly Saturn, Titan, Earth)  Magnetospheric radio emissions (Saturn kilometric and narrowband radiation)  Polarization and direction-finding of radio waves  Calibration of radio antennas on spacecraft Project Participation  Co-Investigator of the Cassini RPWS instrument  Co-Investigator of JUICE-RPWI instrument  Project leader of 2 FWF projects and 1 FFG project