Any heater may treat as a direct one, then the heating power in Watt is prescribed. Or as an inductor for an inductive heating model. In this case the electric current in A and the frequency in Hz is prescribed.

Additionally the heater can be used not as a heat source or sink
but for the representation of the phase shifted alternating
fields in the facility. The superposition of the alternating fields
with the phase difference produces the traveling magnetic field.
In the traveling magnetic field the phase of the maximum field
value travels in axial direction through the furnace. The
traveling magnetic fields (TMF) can be applied to force the melt
convection if the melt is electrically conducting. The TMF model in
*CrysMAS* is used in order to compute the Lorentz force acting on
the melt.

The melt convection in in the TMF field is considered not as back-coupled to the electromagnetic field. Therefore it is enough to compute the distribution of the Lorentz force in the melt only once and then proceed with the fluid dynamics in the melt.

Arbitrary many heaters can be used as careers of the TMF effect. For
activation of the TMF effect first define the existing or new heater
as a direct one and then check the button **
TMF effect ** in the Heaters dialog. If your heater is
an inductive one, then no TMF model can be applied, the alternating
electromagnetic field has everywhere the same phase and differs
from the TMF formulation. The TMF model is an extension of the
alternating field model (AMF) for phase shifted currents.

The dialog fields ** phase shift** and
** Current [A] ** appeare. Additionally the
dialog field ** Frequency [Hz]** is activated.
The values of the phase shift and electric current flowing
azimuthally through the cross-section of the heater region can
be entered. The frequency of the electric current should be
specified in the ** Frequency [Hz]** too.

Press ** Apply ** or ** OK
** after all settings for all heaters are completed.

The frequency of the electromagnetic field is the frequency of the electric current in the heaters with the TMF effect which are treated as inductors. This frequency should be the same for all inductors.

The TMF heater can be used for the simultaneous treatment of the
heating effect and driving of the electromagnetic convection.
It can be used also only for consideration of the
influence of the electromagnetic field on the melt movement. In
this case use a virtual heater with the ** Fixed power ** option
and zero Watt Joule power.