Abstract
ND-GAr is one of three detector systems in the design of the DUNE Near Detector complex, which will be located on the Fermilab campus, sixty meters underground and 570 m from the source of an intense neutrino beam. ND-GAr will consist of a cylindrical 10-bar gaseous Argon Time Projection Chamber (TPC) and a surrounding sampling electromagnetic calorimeter embedded within a superconducting solenoid, the cryostat and yoke for which together serve as the pressure vessel. While various options for the specific configuration of ND-GAr are being explored, essential design work for the detector has moved forward in recent months. This document describes basic mechanical, electrostatic, and gas flow design features of the ND-GAr TPC and presents results of electrostatic simulations of the interior of the pressure vessel for both single and dual-anode arrangements. Simulations are implemented with the Elmer finite-element software suite and related programs.