Modulational instability of electron-acoustic waves: an application to auroral zone plasma T. S. Gill, H. Kaur, S. Bansal, N. S. Saini and P. Bala Eur. Phys. J. D, 41 1 (2007) 151-156 Published online: 01 September 2006 DOI: 10.1140/epjd/e2006-00198-7