  This paper presents a detailed spectral pixel (spaxel) analysis of the ten
Luminous Infrared Galaxies (LIRGs) previously observed with the Wide Field
Spectrograph (WiFeS), an integral field spectrograph mounted on the ANU 2.3m
telescope, and for which an abundance gradient analysis has already been
presented by Rich et al. (2012). Here we use the strong emission line analysis
techniques developed by Dopita et al. (2013) to measure the ionisation
parameter and the oxygen abundance in each spaxel. In addition, we use the
observed H$\alpha$ flux to determine the surface rate of star formation
($M_{\odot}$ yr$^{-1}$ kpc$^{-2}$) and use the [\ion{S}{2}]
$\lambda\lambda6717/6731$ ratio to estimate the local pressure in the ionised
plasma. We discuss the correlations discovered between these physical
quantities, and use them to infer aspects of the physics of star formation in
these extreme star forming environments. In particular, we find a correlation
between the star formation rate and the inferred ionisation parameter. We
examine the possible reasons for this correlation, and determine that the most
likely explanation is that the more active star forming regions have a
different distribution of molecular gas which favour higher ionisation
parameters in the ionised plasma.
