RT info:eu-repo/semantics/bachelorThesis
T1 Introducción a la espectropolarimetría solar
A1 Alvarez Torres, Yasaira
A2 Grado en Física
K1 espectropolarimetría
AB Spectropolarimetry is a branch of astrophysics that focuses on the study of the Sun byanalyzing the polarized light that reaches us from it. This field of study has been very importantin improving our knowledge of the different solar structures, as well as their magnetic fields,their different temperatures, among other characteristics.Throughout this work we will talk about the different solar structures, giving special importanceto understanding how the solar magnetic field works, what exactly are the sunspots and whatare their main parts (umbra and penumbra) and what the granulation of the surface of thesun consists of. Also, understanding theoretical concepts such as the Zeeman Effect and StokesParameters, the foundations have been laid to carry out a practical study using data froma satellite, the HINODE. These data obtained with spectropolarimetry techniques contain theprofiles of the Stokes parameters (I, U, V, Q) in pixels at different wavelengths, of a specificarea of the Sun, where two spectral lines of Fe I ( neutral iron).With these data from the Stokes Parameters we will be able to represent in the first place thedifferent faces that make up the data cube for the intensity parameter I, the image that shows thesunspot that will be the object of study being especially important. In addition, the spectrogramsof the X axes for the rest of the Stokes parameters have also been represented, as well as theirprofiles at different points of the solar continuum.Starting with the practical measurement process, in the first place, a calibration of the data hasbeen carried out using the spectrum of the FTS[7] atlas to convert our data to wavelengths.Once this has been done and taking into account that some physical variables modify the spectraof the Stokes Parameters, we have been able to carry out a series of measurements.The first parameter measured was temperature, obtaining good results that account for thenotable difference in temperature between the umbra and the calm sun. For the calculationof errors, the so-called Monte Carlo method has been used. Next, the values of the magneticintensity in the study region have been measured, having to separate the calculations accordingto whether the criterion of strong field or weak field is fulfilled, obtaining as a result an imagethat accounts for the field differences in the different areas of the sunspot, as well as in the calmsun region. As expected, the results show that in the umbra area the magnetic field is muchmore intense than in the calm sun region. In this case, the error propagation method has beenused. Finally, the velocities of the solar surface have been measured, obtaining as a result afluctuation of 2Km/s. To his error, the Monte Carlo Method has been used again..Finally, three correlations have been made between the different parameters studied, in orderto understand more and draw better conclusions from the results. In the representation ofthe magnetic field against the temperature, it is verified that the areas corresponding to theumbra have a higher value of the magnetic field together with a much lower temperature, asa consequence of the differences in the level of the surface material in that region. . In thecorrelation between speed and temperature, where it is striking that the points are scattered onthe graph between 2 and -2 km/s. This is possibly caused by scattering from the five-minutewobble of the solar surface, along with noise in the data. Finally. The correlation betweenthe magnetic field and the speed was made, where the 5-minute oscillation of the solar surfacebecomes notable again.Yasaira Alvarez Torres ´ 2Introducci´on a la Espectropolarimetr´ıa SolarFinally, to conclude the work, the most interesting phenomena that have been observed withthese traditional measurement methods have been mentioned, such as the Zeeman Effect, whichcauses a splitting of the spectral lines, in this case, of Fe I. Said This splitting is what hasallowed us to measure the magnetic field in the study region, thus obtaining good results fromthe umbra to the calm region. The 5-minute oscillation of the solar surface has also becomenotable, which today continues to occupy an important place in research and, finally, we haveverified the phenomenon of convection, which is affecting the regions of the calm Sun, while inthe area of the sunspot this does not happen.
YR 2022
FD 2022
LK http://riull.ull.es/xmlui/handle/915/30029
UL http://riull.ull.es/xmlui/handle/915/30029
LA es
DS Repositorio institucional de la Universidad de La Laguna
RD 29-abr-2024