1. Centre for Plasma Physics, Queen‘s University Belfast, BT7 1 NN Northern Ireland, UK
2. Institut für Theoretische Physik IV, Fakultät für Physik und Astronomie, D-44780 Bochum, Germany
3. Department of Physics, Faculty of Education-Port Said, Suez Canal University, Egypt
4. Fakultät für Mathematik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
5. Department of Mathematics, Faculty of Science, Fayoum University, Egypt
6. Department of Physics, Faculty of Science, Mansoura University, New Damietta 34517, Egypt