CT Slope Rewrite & MHD Linear Waves

Constrained Transport Slopes

I figured out how to implement the CT slopes function this week. I was thinking about it too hard, instead of passing information like whether or not we’re upwinding, slope side, etc. I just passed in which indices should have 1 subtracted from them to get the right value. It took awhile to implement but it not reproduces what I had before, complete with identical bugs

MHD Linear Waves

To help debug I implemented initial conditions for MHD linear waves. This required refactoring parts of the Grid3D::Sound_Wave function to use magnetic fields and to use a wave’s right eigenvector to set the wave. All of that went reasonably well and is now working.

After getting that working I started with the contact wave. It appears to work perfectly for MHD, though there is some noise in the velocities at the level of \( \sim10^{-15} \). The same noise appears when running with the hydro build, though there it’s only in the x velocity, not all three velocities. The other 3 MHD waves all give significant divergences though after a single time step. The issue appears to be on the edges, possibly only on the X magnetic field on the Y and Z edges since those location are giving most of the non-zero divergences; I’ll look into this next week.