The statistical properties of solar wind temperature parameters near 1 AU observed by Wind

We present a statistical analysis of the temperatures, plasma betas, and temperature ratios for the electron, proton, and alpha-particle populations observed by the Wind spacecraft near 1 AU for ~10 years of data. The mean(median) temperatures are T_e,tot = 12.2(11.9) eV, T_p,tot = 12.7(8.6) eV, and T_α,tot = 23.9(10.8) eV; mean(median) plasma betas are β_e,tot = 2.31(1.09), β_p,tot = 1.79(1.05), and β_α,tot = 0.17(0.05); and mean(median) temperature ratios are (T_e/T_p)_tot = 1.64(1.27), (T_e/T_α)_tot = 1.24(0.82), and (T_α/T_p)_tot = 2.50(1.94). We compared during and excluding interplanetary (IP) shocks, magnetic obstacles (MOs), and slow/fast solar wind. There are differences for slow vs fast wind and during MOs, but with or without IP shocks did not seem to matter. We also compute particle-particle and wave-particle collision rates finding the latter dominates for conservative assumptions of wave amplitude and occurrence rates. Thus, wave-particle interactions should be included when modeling the solar wind.