MEASURING B-MODES IN THE COSMIC MICROWAVE BACKGROUND (CMB) POLARIZATION IS FUNDAMENTALLY IMPORTANT TO COSMOLOGY BECAUSE IT WOULD ALLOW US TO PROBE THE PHYSICS OF INFLATION A MAIN GOAL FOR CMB SCIENCE OVER THE COMING YEARS. HOWEVER THE SUBSTANTIAL FOREGROUND CONTAMINATION FROM MILKY WAY EMISSION MEANS THAN ANY DETECTION MUST PASS STRINGENT RELIABILITY TESTS. IN THIS PROJECT WE WILL PUSH THE MODELING OF FOREGROUNDS TO THE NEXT LEVEL BY (1) MAKING MAGNETOHYDRODYANICAL (MHD) SIMULATIONS OF THE TURBULENT INTERSTELLAR MEDIUM (ISM) AS A BASIS FOR REALISTIC FOREGROUND SIMULATIONS AND (2) CONTINUING TO DEVELOP OUR ISOTROPY-VIOLATION-BASED DIAGNOSTICS FOR CONTAMINATION. THIS PROJECT TAKES ADVANTAGE OF THE TEAM'S EXPERTISE WITH THE CMB AND THE ISM PERMITTING US TO UNDERSTAND BETTER THE STATISTICS OF FOREGROUNDS AND THEIR IMPACT ON CMB B-MODE AND LENSING MEASUREMENTS. THESE RESULTS WILL LET US TUNE OUR ISOTROPY-VIOLATION DIAGNOSTICS AND BOOST THE SIGNAL-TO-NOISE FOR DETECTING FOREGROUND CONTAMINATION. AT THE SAME TIME OUR SIMULATIONS WILL HELP US INTERPRET THE CONSTRAINTS THAT MICROWAVE POLARIZATION DATA (FROM E.G. PLANCK) PUT ON THE PHYSICS OF THE INTERSTELLAR MEDIUM. OUR RESULTS WILL IMPROVE THE B-MODE MEASUREMENTS FOR FUTURE GENERATIONS OF CMB MISSIONS.