Word for emotional state of jealous satisfaction from the whirlwind reaping of others

Consider observing someone getting a taste of their own medicine, reaping the whirlwind or whose chickens are coming home to roost.

In some ignoble, jealous way such situations can be satisfying for observers, particularly if they were, themselves, hurt by the previous state of affairs. Is there a specific term for this hollow laugh of an emotion in an observer?

There may well be a certain cosmic irony to the situation, it might even exemplify vengeance. It exemplifies schadenfreude and, as such, is a lot less noble than the satisfaction of seeing justice done but is, presumably, conveniently mistaken for it.

But none of these seem to be on the button for what seems to be a very common emotional state. Many very precise words for other characteristic emotional states exist in various languages (sehnsucht, hiraeth, schadenfreude, saudade): a loan-word would also be interesting to hear, but this also gives me hope that such a word may exist in English.

Words would be more interesting than phrases, but both will do. (It is, after all, idea easily expressed by description).

Sample sentence: I watched aghast, disgusted and, I admit, with certain a certain sense of X, as the tyrant's great machine -- terror of Megalopolis -- turned, to pin its lifeless, limpid eye upon its own inventor.

I suggested schadenfreude months ago in a comment, and now I wish that I (or someone) had done so as an answer, so that this question could get bumped out of the Unanswered Questions queue. Here (again) is the definition of schadenfreude in Merriam-Webster's Eleventh Collegiate Dictionary (2003):

schadenfreude n, often cap {G[erman], fr[om] Schaden damage + Freude joy} (1895) : enjoyment obtained from the troubles of others

Schadenfreude might be a bit less righteous than the word you're looking for, since it applies to enjoyment of the visiting of whirlwinds on others whether the reapers have sown the wind or not. But there is some justice in that incomplete righteousness, too, since an element of malice lurks in the enjoyment of seeing someone sorely afflicted, even if that person richly deserves punishment. At any rate, MW considers that it has been an English word for more than a century.