  We present optical integral field spectroscopy of the H-alpha-luminous (>1E42
erg/s) central cluster galaxies in the cores of the cooling flows A1664, A1835,
A2204 and Zw8193. From the [NII]+H-alpha complex we derive 2-D views of the
distribution and kinematics of the emission line gas, and further diagnostics
from the [SII] and [OI] lines. The H-alpha emission shows a variety of
disturbed morphologies with velocity gradients and splittings of several
hundred km/s on scales of 20 kpc or more. Despite the small sample size, there
are some generic features. The most disturbed H-alpha emission appears to be
associated with secondary galaxies within 10-20 kpc (projected) of the central
galaxy and close in velocity to the H-alpha. The global H-alpha kinematics
match those of CO(1-0) emission in single-dish data. The [NII]/H-alpha,
[SII]/H-alpha and [OI]/H-alpha ratios vary little with position, local H-alpha
surface brightness or between clusters. We propose that the H-alpha and CO
emission arise in molecular clouds heated by a starburst which has been
triggered by interaction with a secondary galaxy. Such CO emission is known to
trace massive (>1E10 M_sun) compact (<20 kpc) reservoirs of cool molecular gas,
which an infalling galaxy may disturb, distorting the H-alpha morphology and
initiating widespread star formation. We suggest that cloud-cloud collisions in
the undisturbed molecular gas reservoir might be an important excitation source
for the emission line gas in the cores of lower H-alpha luminosity cluster
cores with less intense star formation (abridged).
