TP-05

High Energy Acceleration at Gamma Ray Bursts

Toshiki Tajima (Lawrence Livermore National Laboratory) and Yoshiyuki Takahashi (UAH)

Recent experimental work with Peta-Watt lasers demonstrated efficient Snowplow and Wakefield accelerations of electrons and protons from a stationary target. Used laser beam had 1 micron wavelength at 540 - 560 Joule with a pulse duration of 500 - 1000 femto-seconds. The power of the photons reached   10²⁰ W/cm². GRB suggests far greater power at the source region,   10³⁰ W/cm², but the laser experiments illuminate high intensity photonic acceleration mechanisms. The imemdiate extrapolation of Snowplow/Wakefield acceleration to the very high gamma ray intensity from GRB's indicate that tyhe maximum acceleration energy of protons could be as high as 10²⁴ eV in typical GRB events (e.g., GRB970508). Neutrino intensity on earth from these GRB acceleration is estimated at 10²¹ eV as 1 per km² yr sr. Their interactions with anti-neutrinos in the halo of Virgo Cluster can produce protons and gamma rays above 10²⁰ eV that reach earct at the rate of (0.1 - 1) per km² century sr, without suffering from the propagation limit of the Greisen-Zatsepin-Kuzmin effect.