Determining the Beaming of Io Decametric Emissions: A Remote Diagnostic to Probe the Io‐Jupiter Interaction

We investigate the beaming of 11 Io-Jupiter decametric (Io-DAM) emissions observed by Juno/Waves, Nançay Decameter Array, and NenuFAR. Using an up-to-date magnetic field model three methods to position active Io Flux Tube (IFT), we accurately locate radiosources determine their emission angle θ from local vector. These use (a) updated models IFT equatorial lead angle, (b) ultraviolet (UV) images Jupiter's aurorae, (c) multi-point radio measurements. The kinetic energy Ee− source electrons is then inferred in framework Cyclotron Maser Instability. precise achieved (b c) can be used test effective plasma density torus. Simultaneous radio/UV observations reveal that multiple Io-DAM arcs are associated with UV spots provide first direct evidence arc a trans-hemispheric beam spot. Multi-point probe sources at various altitudes, times hemispheres. Overall, varies function frequency (altitude), decreasing 75°−80° 70°−75° over 10−40 MHz slightly larger values northern hemisphere, independently as time (or longitude Io). Its uncertainty few degrees dominated error on IFT. also vary altitude time. For investigated cases, they range 3 16 keV, 6.6 ± 2.7 keV average.