A wafer is positioned on a wafer support apparatus beneath an electrode such that a plasma generation region exists between the wafer and the electrode. Radiofrequency power is supplied to the electrode to generate a plasma within the plasma generation region during multiple sequential plasma processing cycles of a plasma processing operation. At least one electrical sensor connected to the electrode measures a radiofrequency parameter on the electrode during each of the multiple sequential plasma processing cycles. A value of the radiofrequency parameter as measured on the electrode is determined for each of the multiple sequential plasma processing cycles. A determination is made as to whether or not any indicatory trend or change exists in the values of the radiofrequency parameter as measured on the electrode over the multiple sequential plasma processing cycles, where the indicatory trend or change indicates formation of a plasma instability during the plasma processing operation.