Oscillations and waves in solar spicules

Since their discovery, spicules have attracted increased attention as energy/mass bridges between the dense and dynamic photosphere and the tenuous hot solar corona. Mechanical energy of photospheric random and coherent motions can be guided by magnetic field lines, spanning from the interior to the upper parts of the solar atmosphere, in the form of waves and oscillations. Since spicules are one of the most pronounced features of the chromosphere, the energy transport they participate in can be traced by the observations of their oscillatory motions. Oscillations in spicules have been observed for a long time. However the recent high-resolutions and high-cadence space and ground based facilities with superb spatial, temporal and spectral capacities brought new aspects in the research of spicule dynamics. Here we review the progress made in imaging and spectroscopic observations of waves and oscillations in spicules. The observations are accompanied by a discussion on theoretical modelling and interpretations of these oscillations. Finally, we embark on the recent developments made on the presence and role of Alfven and kink waves in spicules. We also address the extensive debate made on the Alfven versus kink waves in the context of the explanation of the observed transverse oscillations of spicule axes

THE ROAD TO LOS ALAMOS

Une discipline scientifique ne comprend pas seulement de la connaissance pure, mais aussi des images dans la mentalité publique. Influençant le financement et le recrutement de la spécialité, ces images contribuent à son influence dans le monde pratique. L'histoire de la physique nucléaire nous en offre un exemple. Avant 1938 cette spécialité était liée à des images de "transmutation," comprenant non seulement des méthodes scientifiques mais aussi de grands progrès pour la santé et la qualité de la vie ainsi que des armes qui apporteront la paix ou la ruine au mondé entier. Les savants qui sont allés à Los Alamos afin de construire des bombes atomiques l'ont fait surtout parce qu'ils voulaient se défendre contre les Nazis, comme d'autres le faisaient pour le radar et les bombes incendiaires. Mais ils répondaient aussi à des images, fantastiques mais vraies, images existant déjà dans la mentalité générale ; sans ces images, pas de bombe atomique.A field of science involves not only pure knowledge, but also images in the public mind. By affecting funding and recruitment into the field, these images help to determine its destination in the world of action. The history of nuclear physics offers an example. By 1938 the field was linked with images of "transmutation," involving not only scientific methods but images of great improvements for health and wealth, and weapons that would bring world peace or doom. The scientists who went to Los Alamos to build atomic bombs did so chiefly because they wanted to defend themselves against the Nazis, just as others were doing with radar and incendiary bombs. Yet they were also responding to fantastic, but accurate, images that were already deeply established in the public mind ; without those images there would have been no atomic bombs