Megagauss Fields by Automodulating Currents

  • V. Nardi


The magnetic field building-up is related with the filamentation of current channels which is typical of dense plasmas in a variety of experimental conditions. Specifically a sequence of different typical stages is considered for the filamentary current sheath of a coaxial accelerator (plasma focus) in each of which the plasma is in a quasi-stationary state. A description of plasma and field fine structure is given in term of phase-space particle density and electric and vector potentials. The break-up of the filamentary structure generates three-dimensional current loops in the plasma with local amperian currents which can be higher than the accelerator total current. These loops have toroidal and poloidal fields with a maximum of amperian current on the loop axis in the region of poloidal-field peak intensity. Mirror effect on this region creates a steep potential wall with some interruption of the current carrier flow.

Extreme values of current and magnetic field (up to ~108G) are due to the high-energy particles which are produced by the potential wall as in an electronic ram. The time for potential wall and magnetic field building-up is compressed by radiative energy losses for an increasing plasma transparency when the electron cyclotronfrequency reaches the plasma frequency and negative-temperature conditions are created.


Plasma Focus Plasma Column Axial Channel Mirror Effect Virtual Cathode 


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Copyright information

© Plenum Press, New York 1976

Authors and Affiliations

  • V. Nardi
    • 1
    • 2
  1. 1.Istituto Elettrotecnico Nazionale Galileo FerrarisTorinoItaly
  2. 2.Stevens Institute of TechnologyHobokenUSA

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