Vacuum magnetic flux surface measurements on the SCR-1 Stellarator

The Stellarator of Costa Rica 1 (SCR-1), located at the Instituto Tecnológico de Costa Rica, is the first Stellarator of Latin America [1]. In Stellarators, vacuum magnetic flux surfaces are produced only by external coils [2], making respective property measurements possible. Flux surfaces allow the magnetic confinement of plasma, making their characterization important to verify the device's construction. The aim of this work is to present measurements on the flux surfaces in the SCR-1. Mapping of the magnetic surfaces produced in the SCR-1 implied the use of a transparent fluorescent screen covered with ZnO:Zn phosphor which allows the detection of an electron beam, emitted from an electron gun inside the vacuum vessel, that travels around the device following the magnetic field lines. Three highly transparent screens were used: a fixed stainless-steel mesh, an oscillating rod, and an in-house elliptical design called “cuchillo de mantequilla” (butter knife); and results were compared between them. Using the three different methods in the toroidal position 0°, three different nested surfaces were measured. Finally, results were compared with the Poincaré maps from BS-SOLCTRA (Biot-Savart Solver for Compute and Trace Magnetic Fields) and EXTENDER_P (formerly Poincare) codes [3], [4]. The obtained results are consistent with expectations, verifying that the manufacturing process of the coils was handled as designed.