There exists a substantial disagreement between computer simulation results and high-energy density laboratory experiments of the Rayleigh-Taylor instability ( ) .
Motivated by the observed discrepancies in morphology and growth rates , we attempt to bring simulations and experiments into better agreement by extending the classic purely hydrodynamic model to include self-generation of magnetic fields and anisotropic thermal conduction .

We adopt the Braginskii formulation for transport in hot , dense plasma , implement and verify the additional physics modules , and conduct a computational study of a single-mode RTI in two dimensions with various combinations of the newly implemented modules .
We analyze physics effects on the RTI mixing and flow morphology , the effects of mutual physics interactions , and the evolution of magnetic fields .

We find that magnetic fields reach levels on the order of 11 MG ( plasma \beta \approx { 9.1 \times { 10 ^ { -2 } } } ) in the absence of thermal conduction .
These fields do not affect the growth of the mixed layer but substantially modify its internal structure on smaller scales .
In particular , we observe denting of the RT spike tip and generation of additional higher order modes as a result of these fields .
Contrary to interpretation presented in earlier work ( ) , the additional mode is not generated due to modified anisotropic heat transport effects but due to dynamical effect of self-generated magnetic fields .
The overall flow morphology in self-magnetized , non-conducting models is qualitatively different from models with a pre-existing uniform field oriented perpendicular to the interface .
This puts the usefulness of simple MHD models for interpreting the evolution of self-magnetizing HED systems with zero-field initial conditions into doubt .

The main effects of thermal conduction are a reduction of the RT instability growth rate ( by about 20 % for conditions considered here ) and inhibited mixing on small scales .
In this case , the maximum self-generated magnetic fields are weaker ( approximately { 1.7 } MG ; plasma \beta \approx { 49 } ) .
This is due to reduction of temperature and density gradients due to conduction .
These self-generated magnetic fields are of very similar strength compared to magnetic fields observed recently in HED laboratory experiments ( ) .

We find that thermal conduction plays the dominant role in the evolution of the model RTI system considered .
It smears out small-scale structure and reduces the RTI growth rate .
This may account for the relatively featureless RT spikes seen in experiments , but does not explain mass extensions observed in experiments .

Resistivity and related heat source terms were not included in the present work , but we estimate their impact on RTI as modest and not affecting our main conclusions .
Resistive effects will be discussed in detail in the next paper in the series .