Three U.S. senators joined Avital Scharansky yesterday in a public plea to the Soviet Union to release her imprisoned husband, dissident Anatoly Scharansky, and allow him to emigrate.

Sen. Paul Tsongas (D-Mass.) also applied for a visa to travel to the Soviet Union and, in a letter to Soviet ambassador Anatoliy F. Dobrynin, asked to meet with Scharansky in prison in order to "determine for myself his mental and physical condition."

Scharansky began a hunger strike Sept. 27 to protest suspension of his mail and visiting privileges, according to his mother, Ida Milgrom, who last was allowed to see her son Jan. 4. Milgrom told reporters in the Soviet Union she feared for her son's life since he was weak from six months of solitary confinement last year.

Tsongas, accompanied by Sens. Carl Levin (D-Mich.) and John Heinz (R-Pa.), held a press conference on the sidewalk across from the Soviet embassy, then crossed 16th Street NW. Inside the embassy, counselor Sergey B. Chetverikov told them that Tsongas could get a visa to visit the Soviet Union, but would not be able to visit Scharansky, according to a Tsongas aide.

Pointing out that Soviet emigration has fallen off dramatically from its 1979 figure of 51,000 to an estimated 3,000 this year, Tsongas said that "the policy of confrontation with the Soviet Union for its own sake is counterproductive."