Contributed Talk - Splinter Computation

Friday, 25 September 2020, 11:17   (virtual room B)

A hybrid code for coagulation and viscous stirring in protoplanetary disks

M. Beutel, N. Dzyurkevich, R. Strzodka, C .P. Dullemond
Ruprecht-Karls-Universit├Ąt Heidelberg

Planetesimal growth is driven by aggregation of solid particles of sizes covering several orders of magnitude. Monte Carlo methods are often employed to make growth simulations computationally feasible while retaining a high resolution of the particle property space. Among Monte Carlo methods, the Representative Particle Monte Carlo (RPMC) method proposed by Zsom & Dullemond (2008) has the additional benefit of keeping the number of tracer particles invariant despite modeling coagulation and fragmentation processes. In contrast to small dust grains which are mixed via gas turbulence, planetesimals are perturbed in their orbital motion mainly by gravitational interactions such as viscous stirring, frictional heat produced by planets, and to a lesser degree by the gas drag. Gravitational stirring and radial mixing can be accurately described by N-body simulations. In this work, we combine the gravitational N-body code REBOUND with a new code that implements a modified RPMC technique with the goal of simulating the interplay of viscous stirring processes and particle aggregation with high radial resolution and accurate tracking of particle properties. The RPMC method from Zsom & Dullemond (2008), which assumed spatially homogeneous density and velocity distributions in a constant volume, is extended to model collisions between particles on specific orbits by introducing a suitable notion of particle representation. Our modified RPMC code exploits multi-core parallelism effectively, and the hybrid code permits a future extension towards concurrent CPU/GPU execution.