TY JOUR TI Nonlinear physics in the navy. Part 2 KW instability KW nonlinear phenomena KW Hamiltonian KW traveling wave KW soliton KW tsunami KW Ferhulst– Perl equation KW Hamiltonian population dynamics KW separatrix KW COVID-19 KW traveling wave type model of COVID-19 pandemic KW ethnogenesis KW expression of dependence of periods of maximum development of ethnogenesis and pandemic KW generation time KW population growth rate JO Fisheries AU Gaydenok, N.D. PY 2022 IS 2022 PB FSBI "TSUREN"