On Azel, the details of Bombino’s extraordinary guitar playing come back into sharp focus — and that’s this album’s greatest pleasure, track to track. Other experiments emerge, too: Bombino and Longstreth intercut the loping rhythms of Tamashek tradition with the one-drop of reggae in “Timtar” (Memories). (Lest that seem strange: Bob Marley has been as much a hero among generations of Tuareg musicians as Jimi Hendrix, Bob Dylan and Dire Straits.) Bombino may be prodding others there, because no one can say that he’s content to rest with his prodigious gifts. Musically, he’s always moving on to some new destination.