Читать книгу Essentials of MRI Safety - Donald W. McRobbie - Страница 55

Maxwell’s third equation is also known as Faraday’s Law of Induction. We have met dB/dt already in Chapter 1, so clearly this equation is going to have significant implications for us. It states that a time‐varying magnetic field induces an electric field; also, that the electric field lines form complete loops unlike static electric fields (Figure 2.3). The induced electric field is sometimes called “conservative” as it involves no external static charges. Faraday’s Law is also responsible for the detection of the MR signal in an RF receive coil – so it’s important!

Figure 2.3 Electric fields induced by a time‐varying magnetic field form complete loops (unless there are static electrical charges present); dB/dt is into the page.