  Among various long-standing standing problems in superconducting accelerator
magnet development, training is one of the oldest and well-known issues
affecting magnet performance. Understanding physics behind the training process
is crucial for proper mitigation and elimination of this phenomenon in new
magnet designs. This paper discusses application of acoustic emission (AE)
diagnostics to localization and classification of transient mechanical events
in superconducting magnets and characterization of transient energy releases
responsible for premature quenching, memory effects and, ultimately, training.
Prospective of future AE diagnostics development are outlined in connection to
the goals of US Magnet Development Program.
