Creating laboratory gamma-ray bursts with 10\textasciicircum 21 W.cm\textasciicircum -2 laser

Using the Texas Petawatt Laser (TPW) to irradiate thick Au and Pt targets at 10\textasciicircum 21 W.cm\textasciicircum -2 and above, we have created high-density, short-pulse (100 fs) electron, positron and gamma-ray jets with in-situ physical parameters comparable to those found in cosmic gamma-ray bursts. For cm-sized targets, we discover that the hot electron emission is suppressed near the target normal direction, while the positron emission is not. This leads to the creation of angle-selected positron-dominated jets, which have many applications. We will present the results from both experiments and computer simulations, and discuss potential future applications.