Data storage device measuring HAMR media distributions

A data storage device comprising:

• a magnetic media;
• a head actuated over the magnetic media, wherein the head comprises a write coil, a laser configured to heat the magnetic media during a write operation, and a read element;
• and
• control circuitry configured to:
• write a test pattern to the magnetic media by applying a first current to the write coil and a first bias to the laser;
• apply a second current to the write coil and apply a second bias to the laser while the head passes over the test pattern;
• after applying the second current to the write coil and applying the second bias to the laser while the head passes over the test pattern, read the test pattern from the magnetic media using the head to generate a first read signal;
• and
• measure a first noise power of the first read signal.

A data storage device comprising:

• a magnetic media;
• a head actuated over the magnetic media, wherein the head comprises a write coil, a laser configured to heat the magnetic media during a write operation, and a read element;
• a means for applying a current to the write coil and applying a first bias to the laser while the head passes over a test pattern;
• after applying the current to the write coil and applying the first bias to the laser while the head passes over the test pattern, a means for reading the test pattern from the magnetic media using the head to generate a first read signal;
• a means for measuring a first noise power of the first read signal;
• a means for applying the current to the write coil and applying a second bias to the laser while the head passes over the test pattern;
• after applying the second current to the write coil and applying the second bias to the laser while the head passes over the test pattern, a means for reading the test pattern from the magnetic media using the head to generate a second read signal;
• and
• a means for measuring a second noise power of the second read signal.