1. A method for plasma processing of a wafer, comprising: positioning a wafer on a wafer support apparatus, the wafer support apparatus positioned beneath an electrode such that a plasma generation region exists between the wafer and the electrode; supplying radiofrequency power to the electrode to generate a plasma within the plasma generation region during multiple sequential plasma processing cycles of a plasma processing operation; operating at least one electrical sensor connected to the electrode to measure a radiofrequency parameter on the electrode during each of the multiple sequential plasma processing cycles; determining a cycle-averaged value of the radiofrequency parameter as measured on the electrode over the multiple sequential plasma processing cycles; and determining whether or not an indicatory trend or change exists in the cycle-averaged value of the radiofrequency parameter as measured on the electrode over the multiple sequential plasma processing cycles, wherein the indicatory trend or change indicates formation of a plasma instability during the plasma processing operation.