Question

018 10.0 points The magnetic coils of a tokamak fusion re- actor are in the shape of a toroid having an inner radius of 0.519 m and outer radius of 0.999 m. The toroid has 377 turns of wire, each of which carries a current of 18.65 kA. Find the magnitude of the magnetic field at a+b a distance r = from the center of the 2 tokamak. Answer in units of T.

Answer 1

de Coil loop, 3 ws N - such loops b B » Circular d loop C. con Bidar a small section dé shown Let Now from symmeting the magnetic to in field at will be anticlock as shown, due the Current 2 the circular coil turus, running The circle with radius will circular loop Then for this circular loop $B dl = B & de r be a C. we have & B. de с C B. 2tr

B. de B dl Cos o' in the B and de 8ame direction B.d Boll we have & B de B.218 0 c Now for simple loop, from Supere law we can write circuital that Bidé lo for a single c loop we have such loops, for N loops & Bid N Mo I (2 from 0 b c B. 297 = MONI >>

> B = Mo NO Qur But are given, ra atb 2 > B = Mo Na 2 T (a+b) 2 2 ) B = Mo NI I (a+b) given N = 377 a= o.slam b= 0.999 m .-7. X10 x 377 x 18.65 3 Xlo P=18.65 x 103 A 7 (0.510+ 0.929) 8 B = 1.853 T distance Magnetic field at a from the centre of the r oroid.