The Nikkei stock index plunged 2 percent Thursday morning, led by a steep fall in technology shares tracking their U.S. counterparts and selling of exporters on a stronger yen against the U.S. dollar. The 225-issue Nikkei Stock Average fell 819.83 points, or 1.99 percent, from Wednesday to 40,277.86. The broader Topix index was down 27.16 points, or 0.93 percent, at 2,888.05. The dollar at one point fell to around a one-month low in the lower 155 yen range in Tokyo after a news report that former U.S. President Donald Trump, who is set to take on incumbent Joe Biden in the upcoming presidentia…