A review is given of theoretical descriptions of the nonlinear interaction of negative ions with a strong optical field. A brief account is provided of the main features of the structure of negative ions. A detailed analysis is made of the theoretical methods for describing nonlinear processes in negative ions on the basis of the one-electron approximation. The ranges of validity of the reviewed methods are given. Special attention is paid to the role of the electron-electron correlation interaction. The importance of the correlation interaction in weakly nonlinear processes is stressed. The review concludes with the formulation of a number of theoretical and experimental tasks for future investigations of nonlinear processes in negative ions.

@article{Golovinskii:1990,
	author = {P. A. Golovinskii and I. Yu. Kiyan},
	title = {Negative ion in a strong optical field},
	publisher = {Physics-Uspekhi},
	year = {1990},
	journal = {Phys. Usp.},
	volume = {33},
	number = {6},
	pages = {453-476},
	url = {https://ufn.ru/en/articles/1990/6/c/},
	doi = {10.1070/PU1990v033n06ABEH002600}
}