Penrose instabilities and the emergence of rogue waves in Sasa–Satsuma equation M. Pradeepa, N. Vishnu Priya and M. Senthilvelan Eur. Phys. J. Plus, 136 5 (2021) 591 Published online: 28 May 2021 DOI: 10.1140/epjp/s13360-021-01570-1