Magnetic-Induced Force Noise in LISA Pathfinder Free-Falling Test Masses
M. Armano, H. Audley, J. Baird, Pierre Binétruy, M. Born, D Bortoluzzi, E Castelli, A Cavalleri, A Cesarini, A. M. Cruise, K Danzmann, M. de Deus Silva, I Diepholz, George Dixon, R. Dolesi, L Ferraioli, V Ferroni, E. D. Fitzsimons, M Freschi, L. Gesa, D Giardini, F. Gibert, R Giusteri, C Grimani, J. Grzymisch, I Harrison, M-S Hartig, G Heinzel, M Hewitson, D Hollington, D Hoyland, M Hueller, H. Inchauspé, O Jennrich, P. Jetzer, N. Karnesis, B. Kaune, Natalia Korsakova, C. J. Killow, L. Liu, J. A. Lobo, J. P. López-Zaragoza, R Maarschalkerweerd, D. Mance, V. Martín, L. Martin-Polo, F Martin-Porqueras, J. Martino, P. W. McNamara, João Mendes, L. Mendes, N Meshksar, M. Nofrarías, S Paczkowski, M. Perreur-Lloyd, A. Petiteau, P. Pivato, E. Plagnol, J Ramos-Castro, J. Reiche, F. Rivas, D. I. Robertson, G Russano, L. Sala, D. Serrano, J. Slutsky, Carlos F. Sopuerta, T. J. Sumner, D. Texier, James Ira Thorpe, D. Vetrugno, S. Vitale, G Wanner, H. Ward, Peter Wass, W. J. Weber, L. Wissel, A. Wittchen, P. Zweifel
Abstract
LISA Pathfinder was a mission designed to test key technologies required for gravitational wave detection in space. Magnetically driven forces play a key role in the instrument sensitivity in the low-frequency regime, which corresponds to the measurement band of interest for future space-borne gravitational wave observatories. Magnetically induced forces couple to the test mass motion, introducing a contribution to the relative acceleration noise between the free-falling test masses. In this Letter we present the first complete estimate of this term of the instrument performance model. Our results set the magnetic-induced acceleration noise during the February 2017 noise run of 0.25_{-0.08}^{+0.15} fm s^{-2}/sqrt[Hz] at 1 mHz and 1.01_{-0.24}^{+0.73} fm s^{-2}/sqrt[Hz] at 0.1 mHz. We also discuss how the nonstationarities of the interplanetary magnetic field can affect these values during extreme space weather conditions.