Research on Non-Invasive Laser Doppler Current Measurement for Hydrothermal Vents Flow Rates Profile Hongwei Zhang, Songhua Wu, Jintao Liu, Yuanshuai Zhang and Xiaomin Chen EPJ Web Conf., 237 (2020) 07023 Published online: 07 July 2020 DOI: 10.1051/epjconf/202023707023