Joe Gallivan and Powerfield. Tonight's session features legendary drummer Joe Gallivan , whose 40-year career spans be-bop, post-Coltrane experimentalism and avant-garde electronic music. The collective trio Powerfield also features Pat Thomas (electronics) and Gary Smith (guitar). For part of the session, the trio arejoined by a horn section which includes Guy Barker and Elton Dean. And Jez Nelson picks the best of the last few months'CD releases. Producers Steve Shepherd and Kathryn Willgress