MAGNETOSTATICS SEMINAR POWERPOINT P.pptx

Magnetostatics easy understanding

1. PHYSICS SEMINAR

2. BRIEF REVIEW OF MAGNETOSTATICS

3. MAGNETOSTATICS MAGNETOSTATICS is the study of magnetic fields in systems where the currents are steady (not changing with time). It is the magnetic analogue of electrostatics, where the charges are stationary.

4. INTRODUCTION

5. U   U = Energy B = Strength of field d Ʈ = Volume of the element µ = Magnetic permiability

6. What is magnetostatics The magnetization need not be static; the equations of magnetostatics can be used to predict fast magnetic switching events that occur on time scales of nanoseconds or less. Magnetostatics is even a good approximation when the currents are not static – as long as the currents do not alternate rapidly. Magnetostatics is widely used in applications of micromagnetics such as models of magnetic storage devices as in computer memory.

7. Applications of magnetostatics Starting from Maxwell's equations and assuming that charges are either fixed or move as a steady current 𝐽{\ displaystyle \ mathbf {J} }, the equations separate into two equations for the electric field (see electrostatics) and two for the magnetic field. The fields are independent of time and each other. The magnetostatic equations, in both differential and integral forms,

8. NAME FORM DIFFERENTIAL INTEGRAL Guass’s law for magnetism Ampere’s law NAME FORM DIFFERENTIAL INTEGRAL Guass’s law for magnetism Ampere’s law

9. Where ∇ with the dot denotes divergence, and B is the magnetic flux density, the first integral is over a surface 𝑆{\ displaystyle s} with oriented surface element 𝑑𝑆. Where ∇ with the cross denotes curl, J is the current density and H is the magnetic field intensity, the second integral is a line integral around a closed loop 𝐶 with line element 1. The current going through the loop is 𝐼enc.

10. The quality of this approximation may be guessed by comparing the above equations with the full version of maxwell's equations and considering the importance of the terms that have been removed. Of particular significance is the comparison of the 𝐽 term against the ∂𝐷/∂𝑡 term. If the 𝐽 term is substantially larger, then the smaller term may be ignored without significant loss of accuracy.

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