A system for plasma processing, the system comprising: a plasma processing chamber including: a source to provide a plasma in the plasma processing chamber; at least two separate and insulated electrical planes (245, 249, 250, 257) arranged within the plasma processing chamber to control plasma sheaths proximate to the at least two separate electrical planes; and a chuck disposed to support a substrate; at least one bias supply coupled to the at least two separate electrical planes, the at least one bias supply is configured to periodically apply a cycle of an asymmetric periodic voltage waveform to each of the electrical planes, wherein each cycle of the asymmetric periodic voltage waveform includes a first portion with a voltage that increases to a first voltage level, a second portion at the first voltage level, a third portion with a negative voltage swing to a second voltage level, and a fourth portion that includes a negative voltage ramp from the second voltage level; and at least one controller, wherein the controller is configured to obtain at least two ion current measurements, wherein each of the at least two ion current measurements is an indication of ion current proximate to a corresponding one of the separate electrical planes; and control, in response to the at least two ion current measurements, one or more features of the plasma processing chamber selected from the group consisting of magnets, pressure valves, mass flow control, and a physical geometry of the plasma processing chamber. a plasma processing chamber including: a source to provide a plasma in the plasma processing chamber; at least two separate and insulated electrical planes (245, 249, 250, 257) arranged within the plasma processing chamber to control plasma sheaths proximate to the at least two separate electrical planes; and a chuck disposed to support a substrate; a source to provide a plasma in the plasma processing chamber; at least two separate and insulated electrical planes (245, 249, 250, 257) arranged within the plasma processing chamber to control plasma sheaths proximate to the at least two separate electrical planes; and a chuck disposed to support a substrate; at least one bias supply coupled to the at least two separate electrical planes, the at least one bias supply is configured to periodically apply a cycle of an asymmetric periodic voltage waveform to each of the electrical planes, wherein each cycle of the asymmetric periodic voltage waveform includes a first portion with a voltage that increases to a first voltage level, a second portion at the first voltage level, a third portion with a negative voltage swing to a second voltage level, and a fourth portion that includes a negative voltage ramp from the second voltage level; and at least one controller, wherein the controller is configured to obtain at least two ion current measurements, wherein each of the at least two ion current measurements is an indication of ion current proximate to a corresponding one of the separate electrical planes; and control, in response to the at least two ion current measurements, one or more features of the plasma processing chamber selected from the group consisting of magnets, pressure valves, mass flow control, and a physical geometry of the plasma processing chamber. obtain at least two ion current measurements, wherein each of the at least two ion current measurements is an indication of ion current proximate to a corresponding one of the separate electrical planes; and control, in response to the at least two ion current measurements, one or more features of the plasma processing chamber selected from the group consisting of magnets, pressure valves, mass flow control, and a physical geometry of the plasma processing chamber.