# # Program information file # PROGRAM_ID 2024A064 PROGRAM_TITLE Joint IRTF-Juno observations of Jupiter: Simultaneous Measurement of Ion and Neutral Winds PROGRAM_INV1 Ruoyan Wang PROGRAM_INV2 Tom Stallard PROGRAM_INV3 Henrik Melin PROGRAM_INV4 Luke Moore PROGRAM_INV5 James O'Donoghue PROGRAM_SCICAT major planets / satellites PROGRAM_ABSTRACT_BEG Jupiter's main auroral emissions have long been thought linked to the corotation enforcement currents. Recent Juno observations bring new insights, indicating a significantly more complex and diverse system than previously envisioned. As Juno lacks the instrumentation needed to track where these auroral currents close in Jupiter's auroral atmosphere, investigations of the ionospheric currents within the surrounding neutral thermosphere will help to fully understand this long-existing question. Recent near-infrared studies involving simultaneous measurements of the H3+ and H2 emissions in the altitude reveal ion winds in the neutral frame. The result is surprising yet consistent with Juno observations, suggesting an alternative driving mechanism of Jupiter's aurora and providing new thoughts on the coupling between Jupiter's magnetosphere and ionosphere. The high-resolution IRTF iSHELL will be used to resolve both ion and neutral winds from Doppler shifts of emission lines in the K band. A slit of 5'' in length and 0.375'' in width will be placed parallel to the meridian longitude while the planet rotates, capturing four H2 quadrupole and more than ten H3+ overtone emission lines. With a total of 10 nights, each covering 2-4 hours, ion and neutral flows across the entire northern auroral region will be monitored as Jupiter rotates through the central meridian. Two of the nights requested are highlighted for particular importance, exactly before and after the specific time of Juno flyby PJ58, in direct support of the in-situ measurement. PROGRAM_ABSTRACT_END