- #1
eoghan
- 207
- 7
Homework Statement
The magnetic field of the Earth it's approximately [itex]B=3\times10^{-5}T[/itex] at the equator and diminishes with the distance from the center of the Earth as [itex]1/r^3[/itex], as a dipole. Consider a population of electrons on the equatorial plane with energy 30keV, at 5 Earth radius from the center of the Earth.
Considering only the drift caused by the gradient of the magnetic field (i.e. ignore the curvature of the field lines) determine the velocity drift.
Homework Equations
[tex]
v_d=-\frac{\epsilon_\bot}{B}\frac{\nabla B\times B}{qB^2}
[/tex]
Earth radius = 6371km
The Attempt at a Solution
[tex]
|v_d| = \frac{3\times 10^4eV}{(3\times 10^{-5}T)^2}\frac{1}{(5\cdot6371\times10^3m)^3} \approx 10^{-15} m/s
[/tex]
Is this result correct? Because it seems to me to be too low...moreover the next question asks to compute how many time will take for the electron to go around the Earth circumference.
Thank you very much for your help