[DonRotolo]

Or give Tormach a call, perhaps they know of a way to help avoid that.

Also, as James notes, square waves produce RF energy well into the several MHz range. If you can avoid them, do.

Distance helps, as field strength decreases by a cube law.

Make sure both the TIG and the Tormach are well-grounded, ideally with an RF ground in addition to the safety ground (which may be useless at RF)