(2008? Dongguan simulation) the future of mankind to obtain energy through controlled thermonuclear reaction, to continue to occur thermonuclear reaction must be the temperature up to several million

(2008? Dongguan simulation) the future of mankind to obtain energy through controlled thermonuclear reaction, to continue to occur thermonuclear reaction must be the temperature up to several million degrees Celsius! Solution: (1) the greater the speed of the particle trajectory circle radius, to make the OM direction of motion of the ions can not cross the magnetic field, then its movement in the toroidal magnetic field in the largest of the trajectory circle tangent to the outer boundary of the magnetic field circle.

Setting the radius of the trajectory circle as r1, then

r21
+
R21
= (R2?r1)2

Substituting the data and solving for r1 = 0.375m

Set the ionic velocity of this circular motion to be v1, qv1B = m

v21
r1
.

i.e.?v1 =

Bqr1
m
= 1.5×107m/s

(2) Given that the ions are ejected into the magnetic field with a velocity of v2 in the direction tangent to the inner boundary circle and the orbit is tangent to the outer circle of the magnetic field when the ions are ejected into the magnetic field region with the speed of v2 in the direction tangent to the outer circle of the magnetic field, then with that speed Ions shot into the magnetic field region in all directions cannot penetrate the magnetic field boundary.

Setting the radius of the track circle as r2, we get ?r2 =

R2?R1
2
= 0.25m

By?B =

mv2
qr2
= 2.0 T

Answer:

(1) If ions injected into the magnetic field along the radius OM in the region a cannot pass through the magnetic field, the velocity of the particles must not exceed 1.5×107m/s.

( 2) The magnetic induction B of the magnetic field in region b must be at least 2T.