Unipotent almost characters of simple p-adic groups
  Let G be a simple adjoint group and let K=k((\epsilon)) where k is an algebraic closure of a finite field F_q. In this paper we define some geometric objects on G(K) which are similar to the (cohomology sheaves of) the unipotent character sheaves on G(k). Using these geometric objects we define the unipotent almost characters of G(K_0) where K_0=F_q((\epsilon)) and state some conjectures relating them to the characters of unipotent representations of G(K_0). 
G. Lusztig
math.RT