Search results for " UV"
showing 10 items of 168 documents
Monte Carlo Markov Chain DEM reconstruction of isothermal plasmas
2012
In this paper, we carry out tests on the Monte Carlo Markov Chain (MCMC) technique with the aim of determining: 1) its ability to retrieve isothermal plasmas from a set of spectral line intensities, with and without random noise; 2) to what extent can it discriminate between an isothermal solution and a narrow multithermal distribution; and 3) how well it can detect multiple isothermal components along the line of sight. We also test the effects of 4) atomic data uncertainties on the results, and 5) the number of ions whose lines are available for the DEM reconstruction. We find that the MCMC technique is unable to retrieve isothermal plasmas to better than Delta log T = 0.05. Also, the DEM…
Fast photon detection for COMPASS RICH-1
2007
A fast photon detection system has been built and assembled for the upgrade of COMPASS RICH-1. The system is based on multianode photomultipliers coupled to fused silica lenses to collect the light from a larger surface and to guide it to the photocathode, preserving the position information. The emphasis is on the fast response and high rate capability of the detectors and the associated electronics. The photon detection system is now ready and it will be employed in the 2006 COMPASS data taking. We report about the system design and construction.
A facility to validate photomultipliers for the upgrade of the Pierre Auger Observatory.
2020
The Pierre Auger Observatory is undergoing a major upgrade named AugerPrime with the primary aim to add sensitivity to the mass-composition discrimination of ultrahigh-energy cosmic rays. Two different photomultipliers will be added to each water-Cherenkov station of the surface detector of Observatory. To achieve the scientific goals of AugerPrime these photomultipliers have to ensure a linear response to input-light in a wide range. This paper describes a system developed for the validation of AugerPrime-photomultipliers.
TIME-RESOLVED EMISSION FROM BRIGHT HOT PIXELS OF AN ACTIVE REGION OBSERVED IN THE EUV BAND WITH SDO/AIA AND MULTI-STRANDED LOOP MODELING
2015
Evidence for small amounts of very hot plasma has been found in active regions and might be the indication of an impulsive heating, released at spatial scales smaller than the cross section of a single loop. We investigate the heating and substructure of coronal loops in the core of one such active region by analyzing the light curves in the smallest resolution elements of solar observations in two EUV channels (94 A and 335 A) from the Atmospheric Imaging Assembly on-board the Solar Dynamics Observatory. We model the evolution of a bundle of strands heated by a storm of nanoflares by means of a hydrodynamic 0D loop model (EBTEL). The light curves obtained from the random combination of tho…
SOLAR DYNAMICS OBSERVATORY DISCOVERS THIN HIGH TEMPERATURE STRANDS IN CORONAL ACTIVE REGIONS
2011
One scenario proposed to explain the million degrees solar corona is a finely-stranded corona where each strand is heated by a rapid pulse. However, such fine structure has neither been resolved through direct imaging observations nor conclusively shown through indirect observations of extended superhot plasma. Recently it has been shown that the observed difference in appearance of cool and warm coronal loops (~1 MK, ~2-3 MK, respectively) -- warm loops appearing "fuzzier" than cool loops -- can be explained by models of loops composed of subarcsecond strands, which are impulsively heated up to ~10 MK. That work predicts that images of hot coronal loops (>~6 MK) should again show fine s…
Thermal structure of a hot non-flaring corona from Hinode/EIS
2014
In previous studies a very hot plasma component has been diagnosed in solar active regions through the images in three different narrow-band channels of SDO/AIA. This diagnostic from EUV imaging data has also been supported by the matching morphology of the emission in the hot Ca XVII line, as observed with Hinode/EIS. This evidence is debated because of unknown distribution of the emission measure along the line of sight. Here we investigate in detail the thermal distribution of one of such regions using EUV spectroscopic data. In an active region observed with SDO/AIA, Hinode/EIS and XRT, we select a subregion with a very hot plasma component and another cooler one for comparison. The ave…
Medalla a títol pòstum al professor Manuel Sanchís Guarner
1996
Acte acadèmic de concessió, a títol pòstum, de la Medalla de la Universitat de València al professor Manuel Sanchís Guarner. La laudatio va ser llegida per Antoni Ferrando Francès, catedràtic de Filologia Catalana i director del Institut Interuniversitari de Filologia Valenciana.
Medalla al Sr. Vicent Ventura i Beltràn
1995
Acte de Concessió de la Medalla de la Universitat de València a Vicent Ventura i Beltràn, en el Paranimf de l'edifici de la Nau. Intervenen el Sr. Adolf Beltràn, periodista i biògraf de Vicent Ventura, i el propi Vicent Ventura, que delega la paraula en el professor Vicent Alonso.
Medalla al Sr. Manuel Costa
2000
Lliurament de la Medalla de la Universitat de València al Sr. Manuel Costa.
Medalla al Sr. Francesc de Paula Burguera i Escrivà
1997
Concessió de la Medalla de la Universitat de València al Sr. Francesc de Paula Burguera i Escrivà, escriptor i periodista. La laudatio va ser llegida pel Dr. Antoni Ferrando Francès, catedràtic de Filologia Catalana i director de l'Institut Interuniversitari de Filologia Valenciana.