The initial growth of sidebranches in ammonium chloride dendrites

TL;DR

This study investigates the early stages of sidebranching in ammonium chloride dendrites, revealing initial periodicity, growth patterns, and the influence of noise, with implications for understanding dendritic growth dynamics.

Contribution

It provides detailed measurements and analysis of initial sidebranching behavior, highlighting the growth patterns and competition effects in ammonium chloride dendrites.

Findings

Initial sidebranches are approximately periodic and appear about 36 times the tip radius behind the tip.

The initial sidebranch amplitude grows exponentially before saturating.

The observed growth is consistent with noise-driven sidebranching theories, with some quantitative differences.

Abstract

We report measurements for the initial stages of sidebranching during the dendritic growth of ammonium chloride from supersaturated aqueous solution. The earliest sidebranches are approximately periodic; they are first evident about $36 \rho$ behind the tip, where $\rho$ is the tip radius, and have an average initial spacing of about $5 \rho$, though both values show considerable variation. The initial sidebranch amplitude grows approximately exponentially, but quickly saturates as sidebranches compete and coarsening sets in. This initial sidebranch growth is reasonably consistent with what would be expected for noise-driven sidebranches, though there are some quantitative differences.