Laboratory of Photonics and Optical Communications,School of Electronic Science and Engineering,Southeast University,Nanjing 210096,China;
College of Information Science and Technology,Nanjing Forestry University,Nanjing 210037,China;
Department of Physics,Nanjing Xiaozhuang College,Nanjing 210017,China;
College of Physical Science and Technology,Nanjing Normal University,Nanjing 210097,China;
plasmas; modulation instability; density cavity;