Study of head/disc interface dynamics using a thermal asperity sensor

Thermal asperity (TA) sensors have been used to study head/disc interface d ynamics. TA sensor voltage output fluctuates in proportion to the head to d isc spacing changes directly above the sensor. Spacing fluctuations occur i n response to system resonances and other excitations. By analyzing the fre quency content of the TA sensor output the excitation sources have been ide ntified, The TA sensor is found to detect disc run out, micro waviness, dis c flutter, suspension modes, air bearing resonance and slider body vibratio ns. Collapse of the interface, ie., the unsteady slider dynamics, following collision with a "triggering asperity" is also investigated.