= Steady periodic thermal state
{title2=$\theta(x,t+P)=\theta(x,t)$}
A <steady periodic thermal state> repeats each drive period $P$ after the startup transient has decayed. It is time dependent, unlike a time-independent <steady state>. For <angular frequency> $\omega=2\pi/P$, its single-frequency part has the <phasor> representation $\theta(x,t)=\operatorname{Re}\{\widehat\theta(x)e^{i\omega t}\}$. Here $\theta$ is the oscillating <temperature> about the mean profile. Repeating the fitted <amplitudes> and <wave phases> over successive cycles checks that startup drift is small; merely completing one drive cycle is insufficient.
Back to article page
