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Commit 7c45eb7a authored by T. van der Sar's avatar T. van der Sar
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Update 3_drude_model_solutions.md - typo fix

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......@@ -47,19 +47,17 @@ $$
\frac{dv_y}{dt} = \frac{ev_xB_z}{m}
$$
2.
Compute $v_x(t)$ and $v_y(t)$ by solving the differential equations in 1.
We can compute $v_x(t)$ and $v_y(t)$ by solving the differential equations in 1.
From
$$
v_x'' = -\frac{e^2B_z^2}{m^2}v_x
$$
and the initial conditions we find $v_x(t) = v_0 \cos(\omega_c t)$ with $\omega_c=eB_z/m$. From this we can derive $v_y(t)=-v_0\sin(\omega_c t)$.
and the initial conditions, we find $v_x(t) = v_0 \cos(\omega_c t)$ with $\omega_c=eB_z/m$. From this we can derive $v_y(t)=v_0\sin(\omega_c t)$.
We can now calculate the positions using $x(t)=x_0 + \int_0^t v_x(t')dt'$, and similarly for $y$, to find a parametric expression for the position of the particle
We can now calculate the particle position using $x(t)=x_0 + \int_0^t v_x(t')dt'$ (and similar for $y(t)$). We find a parametric expression for the position of the particle
$$
(x(t) - x_0)^2 + (y(t) - y_0)^2 = \frac{v_0^2}{\omega_c^2}
$$
......@@ -71,13 +69,13 @@ Due to the applied electric field $\bf E$ in the $x$-direction, the equations of
$$
m v_x' = -e(E_x + v_yB_z)
$$
This leads to the same 2nd order D.E. for v_x as above. However, for $v_y$ we get
This leads to the same 2nd-order D.E. for v_x as above. However, for $v_y$ we get
$$
v_y'' = -\omega_c^2(\frac{E_x}{B_z}+v_y)
v_y'' = -\omega_c^2(\frac{E_x}{B_z}+v_y),
$$
leading to
which has as solution
$$
v_y(t) = -v_0\sin(\omega_t)-\frac{E_x}{B_z}
v_y(t) = v_0\sin(\omega_t)-\frac{E_x}{B_z}.
$$
By integrating the expressions for the velocity we find:
$$
......
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