Power Generation from Interplanetary and Interstellar Plasma and Magnetic Fields

Authors: Matt Wentzel-Long and Geoffrey A. Landis

Background: The proposal to send an ultra-lightweight probe to a nearby star by accelerating a sail using a laser array will require miniaturization of the spacecraft by many orders of magnitude compared to existing spacecraft. One difficulty for such a concept is reducing the mass of the power source for the onboard computer and scientific instruments. 

Method: In this work, the possibility of generation of power by the sail’s relativistic motion through the ambient magnetic field is analyzed, in which a voltage is created by the induced electric field of a conductor passing through a magnetic field, and a current is established by electrical contact with the ambient plasma. Approximations are estimated for several magnetic environments: that of the interstellar environment, a solar-type star, and the environment of Proxima Centauri as example destinations. 

Results: The results of this analysis were presented at the AIAA Propulsion and Energy Forum in August of 2020. The results show that to generate a power of 10 mW, a sailcraft with the following cross-sectional areas are needed: 5,000 – 12,000 m2 in the interstellar medium, 2,800 – 600,000 m2 in a solar-type interplanetary medium, and < 500 m2 in the interplanetary medium of Proxima Centauri. 

Conclusions: According to this analysis, power can be generated by the passage of a sail through the interplanetary medium, but this may require sizes that are large compared to some currently proposed sails.