Heat-assisted magnetic recording (HAMR) is a magnetic storage technology for greatly increasing the amount of data that can be stored on a magnetic device such as a hard disk drive. Traditional disk drive designs are limited in the amount of data that can be stored, because there is a minimum size for a magnetic field that is used to write data. As data is stored in smaller regions on a disk, it becomes technically impossible or impractical to create a small enough magnetic field, that is also strong enough, to write to a region of that size. HAMR is a technique for overcoming this limit b...