The term "Tycho Magnetic Anomaly" is something of a misnomer when referring to "TMA-0" and "TMA-2", since neither of these are found on the Moon (let alone in Tycho Crater) and neither one of them emits any significant magnetic field, as described in the novel 2010: Odyssey Two.
The name Tycho Magnetic Anomaly-1 (also known as the TMA-1) refers to the strong magnetic field found somewhere in the lunar Crater Tycho by an American scientific satellite.