Consider two ions of equal mass, where one is singly-ionized while...

The radius of the circular path of a charged particle in a uniform magnetic field is given by $r = \dfrac{mv}{qB}$.

For the singly-ionized ion, the charge is $q_1 = e$, so its radius is $r_1 = \dfrac{mv}{eB}$.

For the doubly-ionized ion, the charge is $q_2 = 2e$, so its radius is $r_2 = \dfrac{mv}{2eB}$.

Comparing the two radii, we get $r_1 = 2r_2$. Thus, the circle described by the singly-ionized ion has a radius twice that of the doubly-ionized ion.

Since both ions are projected from the same location with the same initial velocity, their circular paths share a common tangent at the point of projection. Because they are tangent to the same line at the same point, the two circles touch each other at this initial point.