Hydrodynamic instabilities in active cholesteric liquid crystals Carl A. Whitfield, Tapan Chandra Adhyapak, Adriano Tiribocchi, Gareth P. Alexander, Davide Marenduzzo and Sriram Ramaswamy Eur. Phys. J. E, 40 4 (2017) 50 Published online: 24 April 2017 DOI: 10.1140/epje/i2017-11536-2