What does a low thrust apoapsis raising look like?

Say you are in a simple circular orbit, $$r = 1$$ and want to raise your apoapsis to some higher altitude, say an orbit $$r_P = 1, r_A = 2$$

A high thrust spacecraft would to this in one impulse, at $$\Delta v = \frac{2}{\sqrt{3}} - 1 \approx 0.15$$.

But how would a low thrust spacecraft quickly achieve this?

One could of course "emulate" an impulse by only using the engine a short while for each revolution at periapsis. But this does not sound very time-efficient, as the engine isn't in use most of the time. To illustrate this, a circular-circular transfer from $$r=1$$ to $$r=2$$ can be achieved by a spiralling low-thrust craft much faster than by "emulating" a Hohmann transfer.

Is there some similar strategy to "spiralling" when the target orbit is not circular?