  Particles may be emitted efficiently from the solar interior if they are
sufficiently light and weakly coupled to the solar plasma. In a narrow region
of phase space, they are emitted with velocities smaller than the escape
velocity of the solar system, thereby populating a gravitationally bound
density that can accumulate over the solar lifetime, referred to as a "solar
basin." Detection strategies that can succeed in spite of (or even be enhanced
by) the low particle velocities are therefore poised to explore new regions of
parameter space when taking this solar population into account. Here we
identify "direct deflection" as a powerful method to detect such a population
of millicharged particles. This approach involves distorting the local flow of
gravitationally bound millicharges with an oscillating electromagnetic field
and measuring these distortions with a resonant LC circuit. Since it is easier
to distort the flow of slowly moving particles, the signal is parametrically
enhanced by the small solar escape velocity near Earth. The proposed setup can
probe couplings an order of magnitude smaller than other methods for
millicharge masses ranging from 100 meV to 100 eV and can operate concurrently
as a search for sub-GeV millicharged dark matter. The signal power scales as
the millicharge coupling to the eighth power, meaning that even with
conservative assumptions, direct deflection could begin to explore new regions
of parameter space. We also highlight novel features of millicharge solar
basins, including those associated with the phase space distribution and the
possibility for the occupation number to vastly exceed that of a thermal
distribution.
