From one week, the US dollar is heavily manipulated by some big hedge funds. Usd-Jpy (blue) and S&P futures (orange) chart shows what is going on. Two markets always well correlated, in the last week at the collapse of the futures has corresponded a strong increase in the currency pair.
The problem is that almost all the funds have suffered heavy losses with the American stock market. At first, they closed all the gain positions (gold and silver in the first place) to plug the hole, and now they try to recover the losses by "stealing" money to small funds and traders (that is what a fund manager friend of mine told me).