Axel Brandenburg & Nils Erland L. Haugen,  Nordita Copenhagen

Since the work of Biskamp and Mueller (2000, Phys. Plasmas 12, 4889)
there has been serious concern that a major part of the inertial
range is spoiled by using simulations with hyperviscosity.
We present a series of high resolution simulations to show that the
inertial range is unaffected by hyperviscosity. The bottleneck
effect (i.e. a shallower spectrum near the end of the dissipation
range) is a physical effect and its spectral width is the same
with and without hyperviscosity. In nonhelical MHD, hyperviscous
simulations are presented that show a trend towards asymptotic
equipartition in the inertial range.