The role of ions in electron-only reconnection in PHASMA

Here we present the first measurements of ion temperature during electron-only reconnection in the PHAse Space MApping experiment (PHASMA). Both ion and electron temperatures are measured at different phases of the reconnection process to better understand energy allocation in electron-only reconnection. Ion and electron velocity distribution functions (VDFs) are measured using pulsed laser-induced fluorescence (LIF) and Thomson scattering. The linewidth of the pulsed LIF laser is narrowed by a Fabry-Perot etalon to enhance measurement resolution and ensure accurate ion temperature values; the diagnostic system is validated with a well characterized helicon plasma. No significant ion heating is observed. A detailed discussion of the experimental challenges of measuring ion VDFs in PHASMA plasmas will be presented.