Normalized slow wave amplitude as a function of time for T₀ equal to 0.50 MK (top panel), 0.75 MK (middle panel) and 1.00 MK (bottom panel). Blue is the theoretical profile, obtained by solving the dispersion relation. Yellow is the wave amplitude from the simulation, green denotes an exponential fit of the wave maxima. The red dotted line is an exponential fit of the steeply increasing amplitude, due to the runaway effect of the thermal instability. The top figure uses the isobaric growth rate to draw the theoretical wave amplitude, while the bottom two figures use the isochoric one.