Regional Finalist, SARC 2025
Feasibility assessment of satellite-based methods for harnessing auroral solar wind radiation: utilising microwave power transmission.
By Ruann Fourie, South Africa
Abstract:
The global move away from carbon-based energy has accelerated the development of sustainable alternatives. While earlier studies noted technical challenges in capturing auroral energy, this source shows promise as a renewable electricity option. Auroras result from charged particles – mainly electrons and protons – from solar storms entering the atmosphere, ionizing gases and producing visible light. Protons can also emit light resembling hydrogen atoms after electron capture. As these particles breach Earth’s magnetosphere, they accelerate and generate electromagnetic radiation. This energy can be captured via rectennas, converted to microwaves, and transmitted wirelessly from a satellite to a ground station. Despite the altitude of auroral activity (62–186 miles above Earth), microwave power transmission offers a safe, efficient method for longdistance, wireless energy transfer. Though not without risk, it remains the most viable technique for harnessing and delivering auroral energy. Using satellite-based rectennas and transmission systems, this approach could make auroral emissions a functional source of power.
Keywords – Incident protons, Microwave power distribution, Rectenna, Aurora.
Introduction:
Given the global demand for alternative energy sources, exploring nature-driven options like auroral power generation is a logical step. Though rarely considered, auroras can produce up to 10 billion watts of power, making them a potential source of renewable energy.
Capturing all this energy at once isn't possible, and the low, variable energy density means a stationary satellite would be insufficient, necessitating a mobile collection vessel.
By harnessing the electromagnetic radiation produced by particle acceleration in Earth's magnetosphere, a rectenna-equipped vessel can convert this radiation into microwaves. These can then be wirelessly transmitted to a ground station, where another rectenna converts them into electricity. This approach makes it possible to use auroral energy for practical applications.
Literature Review:
Magnetotail
The magnetotail is a stretched region of Earth's magnetosphere formed by the interaction between solar winds and the planet’s magnetic field.
Magnetic reconnection
Solar winds are bursts of charged particles from the sun that travel through space and disturb Earth's magnetic field lines in the magnetotail. These disruptions cause the lines to reconnect, releasing large amounts of kinetic energy, which accelerates particles and generates heat. The energized particles interact with atmospheric gases, transferring energy and producing the visible light displays known as auroras (Chaston).
Auroral kilometric radiation
The most common radiation from disturbances in Earth’s magnetosphere is auroral kilometric radiation, consisting of electromagnetic waves between 10 kHz and 1 MHz (Calvert). The energy in each wave is calculated using (Kokate, Yerokar and Rele):
𝐸 = ℎ × 𝑓 (1)
𝐸 is the electromagnetic energy (J),
ℎ is Planck’s constant (≈ 6.626 × 10⁻³⁴ J·s),
𝑓 is frequency (Hz).
This results in energy values from approximately 6.626 × 10⁻³⁰ J to 6.626 × 10⁻²⁸ J per wave. While small individually, with optimal harnessing over the duration of an aurora, significant total energy can be captured (Fogg, Jackman and Waters).
Direct current generated estimates
To determine the wattage produced by a rectenna (𝑊), we first estimate the incident radio frequency power it receives from a single electromagnetic wave. This requires knowing the wave’s energy (𝐸) and the time it takes to pass through the rectenna’s antenna area (𝑇). Power is then calculated using:
𝑊 = 𝐸 𝑇 (2)
A proposed compact 4 m × 4 m × 4 m S-band patch rectenna for wireless power transfer shows 117.6 W/cm³ output and 47.6% efficiency. (Huang, Li and Du)
Electromagnetic radiation travels (𝑉) at 3 × 10⁸ m/s. Given the 4 m length (𝑋) of the rectenna, the time it takes a wave to traverse it is:
Using wave energies from 6.626 × 10⁻³⁰ J to 6.626 × 10⁻²⁸ J, the power per wave (𝑊) is estimated between 4.97 × 10⁻²² W to 4.97 × 10⁻²⁰ W.
Wave density is the inverse cube of wavelength, with wavelengths between 30 000 m and 300 m, yielding densities from 3.7 × 10⁶ to 3.7 × 10¹² waves/m³. Given the 64 m³ volume of the rectenna, it encounters 2.37 × 10⁸ to 2.37 × 10¹⁴ waves.
Thus, total power ranges from 1.2 × 10⁻⁷ to 1.2 × 10⁻¹¹ W/s. Over an average aurora duration of 5040 seconds, this gives 6.05 × 10⁻⁵ to 6.05 × 10⁻⁸ W at 100% efficiency. Factoring in 47.6% efficiency, expected output drops to 2.88 × 10⁻⁵ to 2.88 × 10⁻⁸ W per auroral event.
Rectenna power harnessing
A rectenna (rectifying antenna) captures and converts electromagnetic radiation into direct current (DC) using a rectifying circuit, typically a diode (David). The diode functions as a one-way valve, blocking the negative half of the alternating current (AC) cycle to produce DC (Abadal, Alda and Agustí).
Microwave power transmission
Microwave power transmission (MPT) enables wireless transfer of large power quantities at microwave frequencies. A power source is converted to DC, which is then transformed into microwaves via a magnetron. These are transmitted and captured by a rectenna, which converts them back into DC (Brown and Eves).
Technological Requirements and Satellite Design
Satellites must withstand extreme conditions, including sub-zero temperatures and electromagnetic interference from auroras. Sensitive electronics should be shielded with metal to protect against radiation (Panagopoulos and Chrousos).
The satellite needs a rectenna to convert auroral radiation into AC and then DC with a diode, which is then converted into microwaves using a magnetron (David). These microwaves are wirelessly transmitted to a ground station equipped with a rectenna to reconvert them into usable DC electricity
Feasibility Analysis
Despite the concept's innovation, the system is not energy efficient. The power generated is less than the energy consumed, making the system impractical as a sustainable alternative to carbon-based energy.
Problem Statement :
Limited research exists on the possibility of incorporating, harnessing the power of auroralphenomena, into feasible alternatives of carbon-based electricity production. As the whole world is resorting to sustainable ways of generating electricity.
Hypothesis
Auroral energy will be a feasible way of generating electricity using a satellite power station and microwave energy transfer technology.
Primary Research
Objective Evaluate the feasibility of a system that captures auroral electromagnetic radiation for power generation.
Secondary Research Objective
Explore the use of microwave power transmission to wirelessly transfer energy between a satellite and a ground station over long distances.
Methodology:
A thorough review of all system components is essential to assess the practicality of generating electricity from auroral radiation. Research does not have to be recent as most uses have been discovered and researched long ago and is well known in the modern day.
Calculations
Estimates must be made to determine the potential energy output during auroral events to assess system feasibility.
Microwave power transmission
A reliable method must be developed to transfer power from atmospheric collection units to ground-based receivers without physical links.
Conclusion:
Given the urgent global need for alternative energy sources and the shift toward sustainability, this research is of significant importance. While the concept of harnessing auroral energy appears promising, the potential energy output is insufficient to justify fullscale development. Microwave power transmission shows potential for efficient energy transfer, though it carries risks for the atmosphere and surrounding life. However, based on the intended geographical locations for energy stations, these risks are minimal in this specific application.
References :
Abadal, G., J. Alda and J. Agustí. “Electromagnetic Radiation Energy Harvesting.” ICT - Energy - Concepts Towards Zero - Power Information and Communication Technology (2014): 80-87. Research Article.
Brown, W. and E. Eves. “Beamed Microwave Power Transmission and its Application to Space.” IEEE Transactions on Microwave Theory and Techniques, Vol. 40, No. 6 (1992): 1239-1246. Research Article.
Calvert, W. “A Feedback Model for the Source of Auroral Kilometric Radiation.” Journal of Geophysical Research, Vol. 87, No. 10 (1982): 8199-8214. Reserach Article.
Chaston, C. “Magnetic Reconnection in the Auroral Acceleration Region.” American Geophysical Union (2015): 3-6. Research Article.
David, H. “What Is a Diode?” Continuing Education (2014): 99-101. Research Article.
Fogg, A., et al. “Wind/Waves Observations of Auroral Kilometric Radiation: Automated Burst Detection and Terrestrial Solar Wind - Magnetosphere Coupling Effects.” Advancing Earth and Space Science (2022): 1-6. Research Article.
Huang, Dajiu , et al. “A Compact and High-Power Rectenna Array for Wireless Power Transmission Applications.” energies (2024): 1-2. Document Article.
Kokate, P., et al. “A Project Report on RF Energy Harvester.” Department of Electronics & Telecommunication Engg. Shri Sant Gajanan Maharaj College of Engineering, Shegaon (2023): 15-60. Research Article.
Panagopoulos, D. and G. Chrousos. “Shielding Methods and Products Against Man-made Electromagnetic Fields.” Science of the Total Environment (2019): 255-262. Research Article.
15. Singh, N., et al. (2021). Tobacco use and lung cancer in India. Journal of Thoracic Oncology, 16(8), 1250–1266. https://doi.org/10.1016/j.jtho.2021.02.004