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Electrically Enhanced Free Dendrite Growth in Polar and Non-polar Systems

Kenneth G. Libbrecht·Timothy Crosby·Molly Swanson
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Abstract

We describe the electrically enhanced growth of needle crystals from the vapor phase, for which there exists a morphological instability above a threshold applied potential. Our improved theoretical treatment of this phenomenon shows that the instability is present in both polar and non-polar systems, and we provide an extension of solvability theory to include electrical effects. We present extensive experimental data for ice needle growth above the electrical threshold, where at $T=-5$C high-velocity shape-preserving growth is observed. These data indicate that the needle tip assumes an effective radius} $R^{\ast}$ which is nearly independent of both supersaturation and the applied potential. The small scale of $R^{\ast}$ and its response to chemical additives suggest that the needle growth rate is being limited primarily by structural instabilities, possibly related to surface melting. We also demonstrate experimentally that non-polar systems exhibit this same electrically induced morphological instability.

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Kenneth G. Libbrecht, Timothy Crosby, Molly Swanson. 2001-01-14. Electrically Enhanced Free Dendrite Growth in Polar and Non-polar Systems. https://doi.org/10.1016/s0022-0248(01)02089-9

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