Physics Department Seminar University of Alaska Fairbanks

J O U R N A L    C L U B

Demoting the Maxwell Equations
Juan Roederer
Emeritus Professor
Physics Dept. & Geophysical Institute

This Journal Club represent Part II of an earlier talk (26 Jan 07) on the "Epistemological and pedagogical questions concerning electromagnetism". Maxwell's perhaps greatest accomplishment was the development of a theory in which several seemingly disparate phenomena of "action-at-a-distance" between electric charges were unified into a picture of "local action" between charges/currents and the electromagnetic field. The local action concept is expressed in the form of a set of differential relations, the Maxwell equations; the action-at-a-distance view is represented in the form of integrals. Both descriptions are mathematically equivalent and they are valid both in relativistic and quantum domains. I will discuss some epistemological, pedagogical and practical implications of these forms, first by analyzing the transition from static to dynamic potentials and the required additional fundamental principles. Then I will discuss two extreme cases: (i) a system of one charge under the action of externally controlled "free" charges and currents, and (ii) a collective system of charges under each others' influences (e.g., a collisionless plasma). Several questions will be addressed, such as "Which are more physical: the charges, the fields or their potentials?"; "Is local reconnection the cause or the consequence of an integral process?"; "What is the cause of magnetospheric field 'dipolarization'?".

Friday, 6 April 2007
Globe Room, Elvey Building
3:45 PM