Current Density

Topics

• Surface Current Density
• Displacement Current
• Polarization Current
• Free Current Density
• Bound Current Density

$\vec{J}\equiv \frac{\mathrm{d}\vec{I}}{\mathrm{d}{a}_{\perp }}$

• $\vec{I}$ is the current
• $a_{\perp }$ is the cross-sectional area of the part the current flows through
  

$\vec{J}=\rho \vec{v}$