Circular (Circumferential) Magnetic Field : The magnetic field in orsurrounding a current carrying conductor pipe, or pipe with an interior current carrying road. (RP 5A5)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}