Induction Heating:
Induction heating is the process of heating a metal object by placing a wound coil carrying a varying, high current at close proximity to the object to be heated. Through the process of induction the metal can be heated to a variety of temperatures, and can take fractions of a second up to continuous operation. This technology has been adopted into the domestic kitchen heating in the form of the induction cooker. This process can also be used for eliminating unwanted oxygen gas in vacuum tubes and for high volume industrial welding. There are a great many industrial users who apply this flameless heating technique for such diverse uses as tempering metals, heating an aluminum strip to seal cardboard milk containers or heating metal pieces to "weld" them onto plastic. For very high temperatures, such as those needed for melting metals, a resistance heater would itself melt. In these applications, a "susceptor" material, such as graphite (which heats well inductively) is within the coil in the shape of a calderon in which the metals to be melted are placed.
There are two mechanisms that generate heat in the metal sample.
Eddy currents are induced into the piece from the strong, changing magnetic field, and the metal's resistance causes the part to heat.
For magnetic metals, there are hysteresis losses caused by the magnetic field reversal each time the field changes polarity.
AC currents, often hundreds of amperes in magnitude and from kilohertz to several megahertz in frequency, are passed through coils often made of water cooled copper tubing. Lower frequencies are used for larger part heating, or when greater penetration depth is required
So 'induction heating' induces Eddy Currents into the object and not in the coil that produces the magnetic flux.
Since I was talking of Electrosurgical Equipment, this makes sense !
An electro-sugical equipment has some sort of a wire loop or a band of metal at its tip. So passing an AC HF current does induce 'heat' and burns the tissue cells. Also in this case the electrode is held slightly away from the site so that induction takes place.
So passing 500KHz into your heater might not do the trick, but using a coil and generating a 500KHz (or more) AC Flux may induce eddy currents into the heater coil.