The relationship between kappa and temperature in energetic ion spectra at Jupiter

A universal energy per charge kappa function fit is simultaneously applied to the spectra of Voyager 2 LECP proton, helium, oxygen, sulfur, and carbon ions during 33 Jovian plasma sheet crossings from 26 to 160 R J . The fits yield an approximately linear relationship between high energy spectral index, κ , and core proton temperature of the form κ (T H ) ≈ η · T H + κ 0 with η = 0.080 keV −1 , κ 0 = 2.86, and T H measured in keV. Core proton temperatures range from 5 to 35 keV with spectral indices ranging from 3 to 6.