The resonant heating and acceleration of protons and selected heavy ions in
coronal holes are investigated by calculating trajectories of individual t
est particles under the influence of gravity, the electrostatic electric fi
eld, the mirror force, and the resonant acceleration due to interaction wit
h dispersive ion cyclotron waves. The transverse heating due to the resonan
ce is also included. We show in general terms how heavy ions can be more th
an mass proportionally heated, emphasizing that wave dispersion may play an
important part in producing very hot heavy ions. We pay particular attenti
on to the ultraviolet coronagraph spectrometer (UVCS) SOHO observation that
the transverse temperature of O5+ is still increasing out to the outer lim
it of observation at similar to 3.5 solar radii. Using both approximate ana
lytical expressions and the trajectory calculations, we find that this obse
rvation can only be reproduced if the magnetic power spectrum falls off at
least as steeply as k(-2), where k is wavenumber. Surprisingly, this conclu
sion holds even when the power spectrum consists of two power laws, if the
inner scale is proportional to the proton inertial length. Once the particl
es are heated transversely by the resonance, the mirror force provides the
dominant outward acceleration and leads to heavy ions which how faster than
the protons. It is shown that it is possible to construct a model which gi
ves reasonable agreement with the UVCS/SOHO data for both protons and O5+ O
verall, we conclude that it is highly likely that the cyclotron resonance i
s responsible for heating protons and heavy ions in coronal holes. However,
we also briefly discuss some data for Mg9+, which do not fit the overall p
icture.