Forces d'origen magnètic durant les operacions de lisa pathfinder
- Autores: Juan Pedro López Zaragoza
- Directores de la Tesis: Miquel Nofrarias Serra (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2020
- Idioma: español
- Tribunal Calificador de la Tesis: Stefano Vitale (presid.), Manuel Domínguez Pumar (secret.), Christian Trenkel Siebold (voc.)
- Programa de doctorado: Programa de Doctorado en Física por la Universidad Autónoma de Barcelona
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
Gravitational waves were predicted by Albert Einstein in 1915 within the General Relativity theory. According to this theory, which represents the present understanding of the gravitational interaction, violent movements in very massive systems generate perturbations which propagate across the space-time, carrying with them the energy of the original system. In 2015, the LIGO collaboration shocked the world with their announcement of a gravitational wave detection coming from the collision of two black holes.
Terrestrial detectors like LIGO have limitations to their detection capacity below the Hertz due to the seismic and human-originated noise. Due to this reason, the European Space Agency (ESA) have decided to put into orbit an observatory of this characteristics in the decade of 2030. Previously, and in order to prove the necessary technology, in December 2015 ESA launched the satellite LISA Pathfinder (LPF), a space mission which had the goal of proving the necessary technologies for the detection of gravitational waves in space. To this end, the satellite performed a pioneer measurement in space. It placed two test masses separated by 38 cm in a nominally perfect free-fall, which means that these two test masses were affected by the force of gravity. A laser interferometer constantly monitored the distance between the two test masses, being this the main scientific measurement of the mission.
Several forces and different effects may perturb the geodesic motion of the test masses. The candidate's thesis focused in the analysis of the data from the magnetic diagnostics subsystem of LISA Pathfinder. The final goal of this subsystem is to be able to predict with great accuracy the contribution coming from magnetic effects to the main scientific measurement of the satellite. The test masses were designed with gold-platinum alloy with the objective of minimising their magnetic moment. Nevertheless, the instrument measurement accuracy is so high that we can see the coupling of the environmental magnetic field with the test masses magnetic moment. This produces forces on the test masses that the interferometer can measure.
In this thesis we have given a review of which are the mechanisms producing these magnetic forces, we have studied the evolution of the magnetic field affecting the test masses and we have analysed the magnetic experiments performed on-board the satellite during the scientific mission operations. All this allowed us to quantify which is the contribution coming from the magnetic effects to the fluctuations of the relative acceleration between the two test masses.
