Features of the cathode plasma formation at the initial stage of a nanosecond spark discharge in airK. I. Almazova, A. N. Belonogov, V. V. Borovkov, V. S. Kurbanismailov, Z. R. Khalikova, G. B. Ragimkhanov, D. V. Tereshonok and A. A. TrenkinEPL, 130 6 (2020) 65002DOI: https://doi.org/10.1209/0295-5075/130/65002