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Reply to “Comment on “Experimental demonstration of electric power generation from Earth’s rotation through its own magnetic field””

Christopher F. Chyba*

Kevin P. Hand

Thomas H. Chyba

  • Department of Astrophysical Sciences and School of Public and International Affairs, Princeton University, Princeton, New Jersey 08542, USA

  • Spectral Sensor Solutions, LLC, Albuquerque, New Mexico 87111, USA

  • *Contact author: cchyba@princeton.edu
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Phys. Rev. Research 8, 028002 – Published 2 June, 2026

DOI: https://doi.org/10.1103/fwtw-h9xd

Abstract

We argued in 2016 that an emf could be generated from Earth’s rotation through its own magnetic field using a magnetically permeable hollow cylinder with a low magnetic Reynolds number Rm [Chyba et al., Phys. Rev. Appl. 6, 014017 (2016)]. Experiments have now generated the appropriate emf and verified five predictions of the theory [Chyba et al., Phys. Rev. Res. 7, 013285 (2025)]. Wijngaarden [Phys. Rev. Res. 8, 028001 (2026)] argues that our 2016 argument is in error. In his model, the magnetization of the cylindrical shell is due to a magnetic field that translates exactly with the velocity of the shell, giving emf=0 always. However, we show that this only holds if magnetic diffusion is negligible, whereas in fact it is significant in the low-Rm case. We do find emf=0 in agreement with Wijngaarden for the special cases of a cylindrical shell operating at high Rm, or for a solid cylinder of any Rm. In these cases, the shell’s field does translate perfectly with the body, there is no diffusion, and current density J=0. In contrast, our device is a hollow cylinder with low Rm so magnetic diffusion contributes alongside advection. For this case, the magnetic field does not rigidly translate with the shell, neither curl J nor J need vanish, and the emf need not be zero.

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Comments & Replies

Comment on “Experimental demonstration of electric power generation from Earth's rotation through its own magnetic field”

Rinke J. Wijngaarden
Phys. Rev. Research 8, 028001 (2026)

Article Text

Original Article

Experimental demonstration of electric power generation from Earth's rotation through its own magnetic field

Christopher F. Chyba, Kevin P. Hand, and Thomas H. Chyba
Phys. Rev. Research 7, 013285 (2025)

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Phys. Rev. Research 8, 028002– Published 2 June, 2026
  • Received 6 August 2025
  • Accepted 30 March 2026
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