Researchers Build 35-Tesla Pulsed Magnet System Using Low-Voltage Design

A team of physicists has developed a compact pulsed magnet system capable of generating magnetic fields up to 35 tesla — roughly 700,000 times the strength of Earth's magnetic field — using a surprisingly low charging voltage of just 400 volts. The system, detailed in a paper posted to the arXiv preprint server on March 13, represents a practical advance in making high-field magneto-optical experiments more accessible to research laboratories.

The instrument, designed by Deepesh Kalauni, Kingshuk Mukhuti, Tao Peng, and Bhavtosh Bansal, pairs the pulsed magnet with an optical fiber-coupled cryostat capable of cooling samples to 5 kelvin — just a few degrees above absolute zero. This combination enables magneto-photoluminescence measurements, a technique used to probe the electronic and optical properties of semiconductors, quantum dots, and other advanced materials under extreme conditions.

What distinguishes the design is its use of electrolyte capacitors in a 75-kilojoule capacitor bank to drive the magnet, rather than the more expensive and bulky film capacitors typically employed in high-field facilities. This engineering choice allows the system to reach its peak field strength while operating at a charging voltage of 400 volts — significantly lower than many comparable systems that require kilovolt-range power supplies. The magnetic field reaches its maximum in approximately 10 milliseconds, a rapid rise time that demands careful engineering of the magnet coil, which the team reinforced with zylon, a high-strength synthetic fiber known for its use in ballistic protection.

The integrated cryostat uses a 4-kelvin helium closed-cycle cryocooler, eliminating the need for continuous liquid helium consumption — an important practical consideration given persistent global helium supply constraints. The closed-cycle design provides a stable low-temperature environment suitable for sensitive optical measurements conducted through the fiber-optic coupling.

While purpose-built national high-field laboratories can achieve fields exceeding 100 tesla, those facilities are expensive, oversubscribed, and often inaccessible for routine measurements. The new system occupies a middle ground: it delivers fields strong enough to reveal Landau quantization and other magnetic-field-dependent phenomena in a wide range of materials, while remaining compact and affordable enough for individual research groups. The 13-page paper includes details on ten figures characterizing the system's performance, suggesting the authors intend it as a reproducible blueprint for other laboratories seeking similar capabilities.