Heisenberg Idempotents on Unipotent Groups

Let G be a possibly disconnected algebraic group over an algebraically closed fieldkof characteristic p> 0, such that its neutral connected component, H = G 0, is a unipotent group. We recall that an algebraic group over k is defined to be a smooth group scheme of finite type over k. Let us fix a prime number l = p. If X is a k-scheme, we use D(X) to denote the bounded derived category