P139倒数第四行末
If the charge enters in the direction of the field lines (场力线), it will not be affected, but if it enters
perpendicularly ([, p?:p?n'dikjul?]垂直地) to the field, it will move at constant speed on a circle. Its radius, called the radius of gyration ([,d?ai?'rei??n]回旋半径), is r = mv/eB, such that . Let the angular speed (角速度) be ? (omega), equal to v/r. Using the formula for r, we find ? = eB/m. If the charge enters at some other angle, it will move in a path called a helix (螺旋状) , like a wire door spring (金属丝制的门弹簧).
P140第二段
Finally, let us release a charge in a region where the magnetic field B is changing with time. If the electron were inside the metal of a circular loop (圆环) of wire of area A as in Fig.10.3, it would experience an electric force induced by the change in magnetic flux (磁通量) BA. The same effect would take place without the presence of the wire, of course.
10.2 HIGH-VOLTAGE MACHINES
(高压设备)
One way to accelerate ions to high speed is to provide a large potential difference between a source of charges and a target. Two devices of this type are commonly used. The first is the voltage multiplier (电压倍增器) or Cockroft-Walton machine （考-瓦氏加速器 ）.
核技术英语-Chapter8- Particle Accelerators
