1. School of Electrical and Computer Engineering, National Technical University of Athens 1 , Zographou, Athens 15780, Greece
2. Department of Physics, William & Mary 2 , Williamsburg, Virginia 23187, USA
3. Department of Mathematics and Physical Sciences, Rogers State University 3 , Claremore, Oklahoma 74017, USA
4. Department of Electrical and Computer Engineering, Old Dominion University 4 , Norfolk, Virginia 23529, USA
5. Plasma Science and Fusion Center, Massachusetts Institute of Technology 5 , Cambridge, Massachusetts 02139, USA