In what may be the first of its kind, Chinese scientists have unveiled a new Stirling engine-powered high-power microwave (HPM) weapon, marking a significant leap in directed-energy warfare technology with possible applications in future urban warfare scenarios.
This month, the South China Morning Post (SCMP) reported that Chinese scientists have claimed to develop an HPM weapon driven by four compact and efficient Stirling closed-cycle heat engines.
SCMP notes that Stirling engines in China’s new HPM design efficiently convert thermal energy into mechanical energy, working together as a reverse heat pump.
The report mentions that the superconducting coil generates a magnetic field with a strength of up to four teslas harnessed to drive HPM waves powerful enough to suppress drones, military aircraft and even satellites.
China claims that it is the world’s first openly reported HPM weapon based on Stirling engine technology.
SCMP states that the intensity of its continuous, steady-state magnetic field reaches 68,000 times that of the Earth’s magnetic field, or close to half the magnetic field strength of the Large Hadron Collider (LHC) in Europe.
It says that the weapon system, which can easily fit into a truck, boasts a significant reduction in energy consumption for generating a strong magnetic field compared with existing technologies. According to preliminary tests, China claims it consumes only one-fifth of the energy required by current methods and can operate continuously for four hours.
The development of low-energy, compact, superconducting magnet systems is essential for large-scale production and use of microwave weapons. The report claims that the Chinese scientists involved in the project achieved the breakthrough partly due to sanctions initiated by former US president Donald Trump.
Since the US government issued an export ban on rare-earth barium copper oxide (ReBCO) and other cutting-edge superconducting materials to China in 2018, Chinese suppliers including Shanghai Superconductor Technology have faced a surge in local demand.
Asia Times noted last month that while directed-energy weapons (DEW) such as lasers and HPMs are touted as the future of counter-drone and anti-satellite weapons, HPMs are known to suffer from low efficiency, high losses in the air and limited range at atmospheric levels.
Those disadvantages have restricted the development of ground-based systems while size and power consumption hinder their use on space-based platforms.
However, recent advances in miniaturization and beam control can offset some of those disadvantages, potentially turning HPMs into practical battlefield weapons.
In March 2023, Chinese scientists from the College of Advanced Interdisciplinary Studies at the National University of Defense Technology invented a compact power source that can significantly decrease the size of HPM weapons, SCMP reported.
The report says that the device can generate electricity up to 10 gigawatts at ten pulses per second, making HPMs powerful enough to fry sensitive electronics in planes, drones and satellites.
SCMP describes the device as an electron accelerator that speeds up electrons in an unusual design sporting two spiral tubes similar to DNA. It says that the spiral tubes were submerged in glycerin, a low-cost liquid that provides excellent insulation, requires no maintenance on the battlefield and eliminates short circuits once air bubbles are removed.
As with the Stirling engine-based design, SCMP mentions that the electron accelerator is small enough to fit on a bookshelf and can be mounted on rooftops or trucks for surprise HPM attacks against overhead targets.
Compact HPM weapons may be strategically deployed on future battlefields characterized by the intensive use of drones, as seen in Ukraine and Israel.
In a May 2023 article for Military + Aerospace Electronics, Jim Romeo mentions that HPMs can destroy computers, electronics and sensors without harming human life, a capability well-suited for urban warfare scenarios that require low collateral damage.
Romeo notes that HPM weapons can neutralize enemy capabilities and combatants nonlethally, offering advantages such as deep magazine capacity, simplified logistics, negligible cost per shot, instantaneous engagement and extreme accuracy.
Along those lines, China may need such capabilities should it decide to invade Taiwan. In a January 2024 article for the Council of Foreign Relations (CFR), David Sacks mentions that if the People’s Liberation Army (PLA) were to enter Taipei, it would face costly urban warfare, having to fight street-by-street in a city of seven million inhabitants.
Furthermore, Sale Lily, in an October 2022 RAND report, describes the PLA’s approach toward urban warfare as “killing rats in a porcelain shop,” indicating the need to avoid collateral damage in trying to wrest Taiwan from urban defenders.
Woon Wei Jong, in an October 2023 Think China article, says that Taiwan’s military is preparing for urban warfare and enhancing its asymmetric warfare capabilities, including acquiring “mobile, small, portable, and AI-enabled” weapons, unmanned aerial vehicles (UAV) and counter-UAV systems.
Jong mentions that the Taiwanese military will use geography, terrain features, urban environments, buildings and critical infrastructure protection measures within tactical defensive areas for layered counter-offensive capabilities and defense-in-depth.
As such, HPM weapons may play an essential role in a potential Chinese invasion of Taiwan in terms of tackling resistance and avoiding collateral damage that could harden Taiwanese resolve to repel invading forces.
However, HPMs may not be the game-changers some are touting them to be.
Timothy Heath and other writers stress that in a 2023 RAND report, strong political leadership, a largely unified and cohesive public, and strong public support for a compelling national cause or ideology is the most durable foundation for a resolute defense.
The Rand report writers state that Taiwan’s ability to resist China in the first 90 days between an invasion and US intervention will hinge on the strength of its political leadership and social cohesion above other variables, such as military effectiveness, durability and firepower.