High frequency electromagnetic field in plasma with negative dielectric constant

A nonlinear mechanism is considered for the penetration of a transverse electromagnetic field into plasma with E=1- omega ₀²<0 and T_e>>T_i. It is shown that the modulated finite amplitude electromagnetic wave produces plasma density fluctuations which form an electro-acoustic wave and transmits the electromagnetic field into the plasma with a velocity of the order of that ion sound. A theory describing the formation and evolution of the electroacoustic waves is developed.