A gamma-ray telescopes intercept a pulse of gamma radiation from magenta, a type of star with a spectacularly large magnetar field. The pulse lasts 0.30 seconds and delivers 7.8 x 10-6 Joule of energy perpendicularly to the 98 m2 surface area of the telescope's detector. The magnetar is thought to be 5.54 x 1020 meter (about 59000 light-years) from earth, and to have a radius of 9.3 x 103 meter. Determine the magnitude of the rms magnetic field of the gamma-ray pulse at the surface of the magnetar, assuming that the pulse radiates uniformly outward in all directions.