IRF
IRF Uppsala
RPF programme
IRF-U Staff
Seminars
Courses
PhD studies
Examensarbete
Workshops
Cluster
...EFW
...Quicklook
Cassini
Rosetta
Solar Orbiter
Intranet
| INSTITUTET FÖR RYMDFYSIK | UPPSALA |
 |
|
| Swedish Institute of Space Physics | (59°50.272′N, 17°38.786′E) |
Internship/Praktik
Magnetic-cloud geoeffectiveness from different solar wind-magnetosphere coupling functions
Student: Alexandre Muller, Institut Supérieur de l'Aéronautique et de l'Espace, ToulouseSupervisor: Vanina Lanabere
Period: spring-summer 2024
Abstract
Magnetic Clouds (MC) are large-scale plasma structures expelled from the Sun into the interplanetary medium. When they reach Earth, these can lead to intense geomagnetic storms. Using the MC database compiled by Lepping et al. and the corresponding data from both the Wind spacecraft and the geomagnetic index Disturbance Storm Time (DST), we provide a coupled theoretical and experimental analysis of the geoeffectiveness of MC depending mainly on the orientation of the axis. We propose a method which uses rotation matrices to change the orientation of the MC and compute the coupling function (a physical quantity which aggregates solar wind parameters to explain ground disturbances) to predict the minimum value of the DST reached. In the end, we demonstrated the validity of the method by performing it on 161 clouds registered between 1995 and 2012. We obtained an empirical relation to link the perturbation in the DST index with the maximum of a MC’s electric field as proposed by Kan and Lee in 1979. We also highlight that the most geoeffective orientation for a given cloud is not always the southern pointing axis but depends on the CA parameter (the minimum distance between the spacecraft and the MC’s axis). Finally we validate our method by showing that on average, results are consistent with the theory. Since the validity of our analysis for a given cloud depends on the goodness of the fit with the Lundquist model, this raises the question whether this model is always the correct one.Results
Final report
![[flow chart]](pipeline.png)
Process pipeline implemented and used in the project.