Whistler‐Mode Transmission Experiments in the Radiation Belts: DSX TNT Circuit Simulation and Data Analysis

  • Jiannan Tu
    Space Science Laboratory University of Massachusetts Lowell Lowell MA USA
  • Paul Song
    Space Science Laboratory University of Massachusetts Lowell Lowell MA USA
  • Ivan A. Galkin
    Space Science Laboratory University of Massachusetts Lowell Lowell MA USA
  • Bodo W. Reinisch
    Space Science Laboratory University of Massachusetts Lowell Lowell MA USA
  • William R. Johnston
    Space Vehicles Directorate Air Force Research Laboratory Kirtland AFB NM USA
  • Michael J. Starks
    Space Vehicles Directorate Air Force Research Laboratory Kirtland AFB NM USA
  • Yi‐Jiun Su
    Space Vehicles Directorate Air Force Research Laboratory Kirtland AFB NM USA
  • David Cooke
    Space Vehicles Directorate Air Force Research Laboratory Kirtland AFB NM USA
  • Gregory P. Ginet
    MIT Lincoln Laboratory Lexington MA USA
  • Umran S. Inan
    Department of Electrical Engineering Stanford University Palo Alto CA USA
  • David S. Lauben
    Department of Electrical Engineering Stanford University Palo Alto CA USA
  • Yoshizumi Miyoshi
    Institute for Space‐Earth Environmental Research Nagoya University Nagoya Japan
  • Shoya Matsuda
    Graduate School of Natural Science and Technology Kanazawa University Kanazawa Japan
  • Yoshiya Kasahara
    Graduate School of Natural Science and Technology Kanazawa University Kanazawa Japan
  • Hirotsugu Kojima
    Faculty of Engineering Kyoto University Kyoto Japan
  • Iku Shinohara
    Japan Aerospace Exploration Agency Sagamihara Japan

抄録

<jats:title>Abstract</jats:title><jats:p>High‐power transmission experiments in the very low frequency (VLF) mode have been conducted by the US Air Force Research Laboratory’s Demonstration and Science Experiments (DSX) satellite in the radiation belts using a novel transmitter that automatically tunes to find the resonance frequency of the transmitter circuit including the antenna. The resulting voltage–frequency curves are used to derive antenna impedance at the resonance. The analysis shows that the antenna reactance is far less than that of a dipole antenna in free space. The derived radiation resistance is up to several tens of kilo Ohms. Most interestingly, it is found that the radiation resistance is inversely proportional to the square of transmission wave frequency. The transmitted power can be up to 80 W for the DSX transmitter with an 82‐m long tip‐to‐tip antenna, showing that the high‐power VLF transmission is feasible. Whistler wave transmission inside the higher‐density plasmasphere is more efficient. Data analysis indicates that the antenna impedance does not vary systematically with the antenna orientation angle relative to the ambient magnetic field. The previous dominant theoretical studies yield not only incorrect values of the impedance but a completely different frequency dependence than that derived from DSX experiments. Instead, the recent theories correctly capture both the antenna impedance magnitude and the frequency dependence.</jats:p>

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