Prepulse controlled splitting of relativistically self-guided channel and suppression of Raman forward scattering instability

The effects of laser prepulse on splitting of a relativistically self-guided channel and suppression of Raman forward scattering instability were studied in an underdense plasma. Probing interferometry, shadowgraphy and spectrometry techniques were used. The propagation of the laser beam could be controlled by changing the prepulse intensity to show self-guiding or channel splitting. The results show that the instability is significantly reduced if the gas target is preionized, thus identifying ionization wakefield as the seeding mechanism for this process.