Biological process

up regulation of thymocyte apoptosis, up-regulation of thymocyte apoptosis, upregulation of thymocyte apoptosis

Any process that activates or increases the frequency, rate or extent of thymocyte death by apoptotic process.

positive regulation of immature T cell apoptosis

Note that a thymocyte is an immature T cell located in the thymus (CL:0000893).