Plasma produces two related fields. The one that does the really heavy lifting is the near-field, and this extends six inches from the tube in all directions. After six inches, it becomes far-field, which isn't as effective as near-field, although it still works efficiently enough to disinfect and clear mold from a home.
So it still works on the body, just not to the same extent and power as near-field.
If you are unable to be within the near field, suggest you remain within 5 feet of the tube for decent efficacy. This is where I have most of my family when the tube is running.
I have affected targets further than this, but the field decreases in power as you go further away.
To give you an idea of the field, a WIFI router is only 1 watt of power maximum by law. You can see how large the field is with your phone. The plasma output from the SC is 40 watts.