Time series of volume-averaged quantities in 3D MTI with whistler suppression. From top to bottom: Specific kinetic energy, specific magnetic energy, and thermal diffusivity. The left column shows our MTI runs without external forcing: without suppression (gray starred line), with weak suppression (solid blue), and with strong suppression (solid gold). In the right panel external forcing is introduced. For comparison, also shown is a pure-forcing run (solid red line) with isotropic thermal diffusion (no MTI). MTI turbulence decays with strong whistler suppression, but the addition of forcing revives it.