Arturo López Ariste
Inst. Astrof. Canarias (IAC) (Tenerife, Espagne)
THEMIS was designed and built as a solar telescope dedicated to spectropolarimetry and, as such, presented an unseen absence of instrumental polarisation and a powerful multiline spectrograph. The spectropolarimetric measurements have allowed a powerful insight into the plasma dynamics of the solar atmosphere, including studies of the magnetic field topology supporting the plasma in prominences against gravity, or of the chaotic and unstructured field created by local dynamos in the quietest photosphere. But THEMIS also leaves the Sun itself to approach the observation of Mercury's exosphere and its solar-wind driven dynamics.
Being a polarisation-free telescope, polarimetry can be taken to unprecedented levels: one polarized photon per 100 000 emitted is a subtle indication of the precise quantum behaviour of a given atom. The observation of the polarisation of resonance scattering emissions from atoms is benchmarking our knowledge on the quantum behaviour of atomic systems in the particular physical conditions of the solar atmosphere, and I shall show examples of that from THEMIS data.
This talk is an introduction to the capabilities of this extraordinary tool called THEMIS, and an open call for other unforeseen uses.
, Institut d'Astrophysique de Paris