It has been well recognized that hot electrons are produced due to collective absorption of the intence laser radiation arround the critical layer and penetrate into the high density core region. Under the stationary production of hot electrons, the cold electron return current is induced to retain the charge neutrality and the ion accoustic turbulence is then driven by the return current.
The collisionless Vlasov equation for hot electrons and fluid equation with the anormalous collision effects for cold electrons are used. For the plane and spherical geometry, the reduction of the hot electron energy flux due to the electrostatic field is investigated. As the results, it is found that a large electrostatic potential, say, |eφ/Th| 1 2 is built up due to the anormalous resistivity and only about 10% (spherical) or 20% (plane) of the free streaming energy flux limit can penetrate into the core region.