I= Problem 2: A 5.0-mm-diameter proton beam carries a total current of = 1.5 mA. The current density in the proton beam, which increases with distance from the center, is given by J = Jedge (r/R), where R is the radius of the beam and Jedge is the current density at the edge. Determine the value of Jedge- a) Fig. 3 shows the cross section of the beam. Compute the current dI flowing through the ring of radius r and width dr shown in the figure. Notice that for small dr the area of the ring can be approximated by the area of a rectangle that you can get by "unrolling" the ring.

I= Problem 2: A 5.0-mm-diameter proton beam carries a total current of = 1.5 mA. The current density in the proton beam, which increases with distance from the center, is given by J = Jedge (r/R), where R is the radius of the beam and Jedge is the current density at the edge. Determine the value of Jedge- a) Fig. 3 shows the cross section of the beam. Compute the current dI flowing through the ring of radius r and width dr shown in the figure. Notice that for small dr the area of the ring can be approximated by the area of a rectangle that you can get by "unrolling" the ring.