Ion and electron drifts (earth's magnetic field)

Metadata

• CONTEXTO : Segundo ciclo universitário
• AREA: Física
• DISCIPLINA: Física e Tecnologia dos Plasmas
• ANO: 4
• LINGUA: en
• AUTOR: Vasco Guerra
• MATERIA PRINCIPAL: Single particle motion I
• DESCRICAO:
• DIFICULDADE: *
• TEMPO MEDIO DE RESOLUCAO: 300 [s]
• TEMPO MAXIMO DE RESOLUCAO: 600 [s]
• PALAVRAS CHAVE:

(F. F. Chen ~ 2.8) Suppose the earth's magnetic field is \(3\times10^{-5}\) T at the equator and falls off as \(1/r^3\) as in a perfect dipole. Let there be an isotropic population of 1 eV protons and 30 keV electrons, each with density \(n=10^7\) m\(^{-3}\) at \(r=5\) earth radii in the equator plane.

(a) Compute the ion and electron \(\vec{\nabla} B\) drift velocities.

(b) Does an electron drift eastward or westward?

(c) How long does an electron take to encircle the earth?

(d) Compute the current ring density in A/m\(^2\).