When Ira Sullivan is in the right mood, he’s one of the very best living examples of the spontaneity and freedom that, to the romantic mind, used to characterize jazz. Trumpet, flugelhorn, peck horn, flute, saxophone–he’s found a unique bop style adapted to each one’s particular construction. On trumpet and tenor sax, his best instruments, he’ll open up long lines of intricate, intense melody by inserting impulsive, flaring ideas that make your head spin and stretch the instruments to their limits. It’s exciting music, a wonderful adventure in the far territories of classic jazz harmony and rhythm (in Sullivan’s Chicago period more than three decades ago, his band was among the first to play Ornette Coleman’s songs). But Sullivan has to be in the mood–some of the well-rehearsed bands he’s brought to Chicago in recent years have been way too mellow. Fortunately, for this return home he’ll work with two of the truly fresh bands on the Chicago scene. Tonight he’ll be joined by the Green Mill All-Stars, experts in generating visceral heat: Willie Pickens (piano), Brian Sandstrom (bass), Robert Shy (Drums), and Ed Peterson, whose tenor sax could provoke Sullivan to combat. On Saturday and Sunday he’ll rejoin the tough, probing Jim Cooper Quartet (I’m especially partial to Cooper’s vibes and Bob Dogan’s piano), with whom he recorded on their recent Delmark disc Tough Town. Tonight, 9 PM, Saturday, 8 PM, and Sunday, 2-6 PM, Green Mill, 4802 N. Broadway; 878-5552.