The Harish-Chandra–Howe
local character expansion expresses the characters of reductive, -adic groups in
terms of Fourier transforms of nilpotent orbital integrals on their Lie algebras, and
Murnaghan–Kirillov theory expresses many characters of reductive, -adic groups
in terms of Fourier transforms of semisimple orbital integrals (also on their Lie
algebras). In many cases, the evaluation of these Fourier transforms seems
intractable, but for , the nilpotent orbital integrals have already been
computed. We compute Fourier transforms of semisimple orbital integrals using a
variant of Huntsinger’s integral formula and the theory of -adic special
functions.