- Why does the particle spiral outward instead of staying in a circle of constant radius?
- The particle gains kinetic energy each time it is accelerated by the electric field in the gap. In a uniform magnetic field, the radius of the circular path is proportional to momentum (r = mv/qB). As speed (v) increases, so does the radius, causing the particle to trace a larger semicircle each time it returns to a dee, resulting in the outward spiral.
- What happens if the frequency of the oscillating electric field doesn't match the cyclotron frequency?
- Acceleration becomes inefficient or stops. For optimal energy gain, the electric field must reverse polarity exactly when the particle arrives at the gap, so it is always pushed forward. If the frequencies are mismatched, the particle may encounter a decelerating field, lose energy, or simply not be accelerated consistently, breaking the resonant condition essential for the cyclotron's operation.
- Why can't a cyclotron accelerate particles to arbitrarily high speeds?
- This simulator uses classical (non-relativistic) physics, where the cyclotron frequency is constant. In reality, as particles approach a significant fraction of the speed of light, their relativistic mass increases. This changes their orbital frequency, causing them to fall out of sync with the fixed-frequency oscillating electric field, imposing a fundamental energy limit on simple cyclotrons.
- What is the role of the magnetic field? Why can't we just use a strong electric field?
- The magnetic field's sole purpose is to bend the particle's path into a closed loop, steering it back to the acceleration gap repeatedly. A linear accelerator uses only electric fields, but the particle passes each gap only once. The magnetic field in a cyclotron enables reuse of the same relatively small voltage gap many times, allowing a compact design to achieve high energies.