High Resolution Spectra of Jupiter’s Decametric Emission using the Long Wavelength Array Station 1

Abstract:

The Long Wavelength Array Station 1 (LWA1) provides excellent spectral and temporal resolution of Jupiter’s decametric radio emissions over the bandwidth of 10-40 MHz. Using the full Stokes capabilities of LWA1 we show high resolution data of many well-known decametric features in Jupiter’s spectrum including nested-arc structure, modulation lanes, S-bursts, narrow band N-events, and S-N event interactions. These new data allow for the testing of emission mechanisms relating to emission geometry, source locations, propagation paths, and S-burst acceleration models. In particular, LWA1 data showing simultaneous modulation lanes in both polarizations for a Jupiter Io-C event suggest that both polarizations might be coming from the same hemisphere, contrary to the emission theory. The well-known S-bursts show very complex structures such as frequency drifting, source splitting, and combination. Initial calculations of S-burst frequency drift rates are similar to previous data but new measurements at higher frequencies will help understand the electron acceleration mechanism. Moreover, some S-bursts show interaction with N-events by either triggering or quenching the resonance set up in the source emission zone. The linearly polarized feeds on LWA1 instrument also show excellent Faraday fringes in the Jupiter observations. Further analyses are needed to understand these phenomena and other features of Jupiter’s decametric spectrum. We show Jupiter spectra and highlight the new capabilities of the LWA1 telescope.