  Quench heaters are often an essential part of protecting a superconducting
accelerator magnet during a quench. Their purpose is to spread the quench
throughout the coil as quickly as possible. They are located in areas of high
magnetic fields and are thus prone to magnetoresistive phenomena and the Hall
effect. Such influences can cause currents to distribute unevenly in the
heaters, which results in uneven heating. This can reduce the effectiveness of
the heaters and even endanger them due to excessive local heating. Also, the
heater geometry itself can be the cause of uneven current density.
  In this paper we investigate by numerical simulations the importance of the
magnetic effects on quench heater performance and whether they should be taken
into account in the design. The main interest is in the Hall effect, which was
perceived as the most likely source of trouble for the design of quench
heaters. We use a simple phenomenological approach for modeling the Hall
effect, utilizing values from the literature for the Hall coefficients.
Magnetoresistance is also considered and the impact of heater geometry on
current distributions is briefly visited.
  The conclusion of this research is that magnetoresistance plays an
insignificant role in the functioning of quench heaters. The Hall effect can
clearly be more influential, but nevertheless should not pose any problems in
most cases. Current distributions due to heater geometry should be take into
consideration in the design phase and, if needed, take measures to equalize the
current density by using, for example, copper cladding in appropriate
locations.
