1. Sources of the Magnetic Field......moving charges, currents and other effects

2. A Moving Point Charge Since a moving charge is effected by a magnetic field - is there a “symmetry” here? Just how does this interaction take place? Answer: A moving charge establishes or creates a magnetic field!

3. The Biot-Savart Law Currents produce magnetic fields:

4. Examples using the Biot- Savart Law …(read 29-1,2 very carefully!) The Current Loop The Solenoid Long Conducting Wire

5. Forces on Conducting Wires Since a conducting wire creates a magnetic field, two conducting wires should interact... This leads to a precise definition of the Ampere

6. Gauss’ Law for Magnetism The net magnetic flux through any closed surface is always zero...

7. Ampere’s Circuital Law... When the current I is constant… Just like Gauss’ Law, this is really only useful as a calculating method when there is a high degree of symmetry

8. Magnetization in Matter Ampere’s Circulation Model explains magnetism as the result of amperian current which seems to anticipate the idea of magnetic dipole moments and leads to a definition of magnetization:

9. Magnetization in Matter In a magnetic field B the presence of a material affects the magnetic field in a manner described by:

10. Flavours of Magnetization: Paramagnetic: are materials for which a small increase in B (positive susceptibilty) occurs when placed in an external field Diamagnetic: materials that have negative susceptibilty (Bisthmus for example) Ferromagnetic: large (HUGE) suscpetibility

11. More on Ferromagnetism... Domain Theory: simulation of domains in a 10nm NiFe film undergoing rapid magnetization reversal simulation of domains in a 10nm NiFe film undergoing rapid magnetization reversal Hysterisis and “Soft” and “Hard” ferromagnets Geological Field Reversal: paleomagnetism paleomagnetism