1. Capturing inflows and outflows requires 3D. Enrichment is biased. The first stars were formed in dark matter minihalos around redshift z ≈ 20. In order to accurately reproduce this environment we employ a fully cosmological simulation inside a 1 Mpc 3 (comoving) volume. Zooming in on the densest gas using adaptive mesh refinement (AMR), we insert a metal-free Population III star (or stars). The stars ionize the surrounding gas creating an HII region before exploding as core collapse supernovae. We follow the expanding ejecta at high resolution for tens or hundreds of millions of years until it has recollapsed to form a new generation of stars. The early universe is a multi-scale problem. 40 kpc (Above) Density projections centered on a 10 6 M  minihalo. A single 60 M  star has partially ionized the surrounding gas, leaving behind a wall of dense neutral clouds. (Far Right) A supernova blastwave has been inserted at high resolution with 10 51 ergs of kinetic energy and cell size 0.05 pc. Density-metallcity phase diagram of the gas in a recollapsing dark matter halo 200 Myr after the explosion of 7 supernovae. The solid lines show the average metallicity contribution from each supernovae (color) and total (black). Fragments from the first few supernovae contribute more to the collapsing gas than the relatively diffuse ejecta from the final few supernovae. Radially-averaged density profiles of gas in a cosmological (solid) or spherically symmetric (dashed) minihalo heated by ionizing radiation. Instabilities in a supernova blastwave are enhanced when it has expanded to R SN ≤ 100 pc and interacts with the dense shell or neutral clouds along the cosmic web filament. (Left) Density slices through a supernova blastwave inside a uniform density background. The canonical blastwave phases are free expansion, Sedov-Taylor, and momentum-conserving “snowplow”. Sizes are in parsecs. (Left to right) Density, temperature and metallicity projections 8.5 Myr after a single supernova. The blastwave has been completely fragmented. Some ejecta escapes the virial radius (180 pc) while the filaments of the cosmic web resume flowing back into the central gas cloud. 1100 pc360 pc (Right) This supernova is well- described by the simple Sedov-Taylor solution. Explosions in a realistic background are subject to additional instability due to interaction with the non-uniform cosmic web. Ejecta and fallback are inhomogeneous. Cross-section of the ejecta particles through the middle of a super-bubble, 72 Myr after the sequential explosions of 7 supernovae. The ejecta tracer particles are colored according to their progenitor supernova. Large inhomogeneities remain between the ejecta from different supernovae. Slice through the recollapsing remnant showing the vorticity magnitude, 200 Myr after the 7 supernovae. A larger vorticity implies a shorter mixing timescale. The metal-rich fragments are shown with black tracer particles. The ejecta fragments remain mostly unmixed with one another down to the resolution limit of our simulations, however the vorticity rises as the gas falls onto the dense central cloud. Average rate of gas inflow (solid) and outflow (dashed) through the central 10 pc of a minihalo following a single supernova. Inflow from the cosmic web resumes relatively quickly after 1 Myr while the accretion of metal fragments is bursty and takes a longer time. Metals All gas Ejecta-rich clumps falling back onto the recollapsing gas cloud at the center of a dark matter halo are biased towards the ejecta that are compressed into the momentum-conserving snowplow thin shell that becomes fragmented due to interaction with the cosmic web. In the case of a single supernova this bias is towards the outer ejecta layers, while for multiple supernovae the bias is towards earlier supernovae. Jeremy Ritter is a native Texan. After spending several years as a programmer, he returned to school to pursue a career in computational astrophysics. He is currently in his 3 rd year as a PhD student at the University of Texas at Austin. Free expansion Sedov-Taylor Snowplow Density slices with ejecta tracer particles 40 Myr after the explosion. Ejecta-rich fragments are falling back in streams that intersect with the inflowing pristine hydrogen from the cosmic web filaments. 4 kpc 400 pc 40 pc