10 電磁 III How is an aurora so thin yet so tall and wide?

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10 電電 III How is an aurora so thin yet so tall and wide?

Transcript of 10 電磁 III How is an aurora so thin yet so tall and wide?

  • 10 III How is an aurora so thin yet so tall and wide?

  • Sections

  • 10-1 The electric field and the magnetic fieldElectromagnets and permanent magnets

  • 10-1.1 The definition of B

  • The tracks in a bubble chamber

  • The SI unit for B1 tesla = 1T =1 N/Am=104 gauss

  • Magnetic Field Lines Magnetic vs. electric dipoles A horseshoe and a C-shaped magnets

  • 1 A 5.3 MeV proton

  • 10-1.2 Crossed Fields: Discovery of the ElectronA cathode ray tube Thomsons procedure:E = 0, B = 0, ,

  • Calculation

  • 10-1.3 Crossed Fields: The Hall EffectBy the conduction electrons in copper:

  • 2 A cube generator

  • 10-1.4 A Circulating Charged Particle

  • The frequency and angular frequency

    Helical Paths

  • 3 The Mass Spectrometer ()

  • Isotope Separation

    Centrifuge and diffusion chamber

  • The pitch () of the helical path

  • 10-1.5 Cyclotrons and SynchrotronsFermilab: 6.3km ring ()

  • SynchrotronsThe resonance condition:When proton energy > 50Mev:Out of resonance (relativistic effect) A huge magnet (4106 m2) is needed for high energy (500Gev) protons The proton sychrotron at Fermilab can produces 1Tev proton

  • 10-1.6 Magnetic Force on a Current-Carrying Wire

  • For a wire segment: Magnetic Force

  • 4 A length of wire with a semicircular arc

  • Calculation

  • 10-1.7 Torque on A Current LoopF2 and F4 cancel F1 and F3 form a force couple

  • 5 A galvanometer for analog meters

  • 10-1.8 The Magnetic DipoleThe magnetic dipole moments

    The magnetic potential energy

  • 10-2 Magnetic Fields due to CurrentsConventional rocket EM Rail Gun

  • 10-2.1 Calculating the Magnetic Field due to a currentThe law of Biot and Savart

  • Magnetic Field Due to a Current in a Long Straight Wire

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  • Integration

  • Magnetic Field Due to a Current in a Circular Arc of Wire

  • 6 What B does the current produce?

  • 10-2.2 Two Parallel Currents

  • 7 The Field Between Two wires

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  • 10-2.3 Amperes LawComparing Gauss law and Amperes lawAmperes law

  • The Magnetic Field Outside a Long Straight Wire with Current

    EMBED Equation.2

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  • The Magnetic Field Inside a Long Straight Wire with Current

    EMBED Equation.2

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  • 7 A hollow conducting cylinder

    EMBED Equation.2

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  • 10-2.4 Solenoids and ToroidsMagnetic Field of a Solenoid ()Magnetic Field of a Toroid ()

  • Magnetic Field of a Solenoid

  • Magnetic Field of a Toroid

  • Tokamak Fusion Test Reactor

  • 10-2.5 A Current Carrying Coil and a Magnetic DipoleA current loop and a bar magnet

  • Magnetic Field of a Coil

    EMBED Equation.2

    6

    1

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  • IV