28 research outputs found
HKT manifolds: Hodge theory, formality and balanced metrics
Let be a compact HKT manifold and denote with
the conjugate Dolbeault operator with respect to ,
,
where is the adjoint of . Under suitable
assumptions, we study Hodge theory for the complexes
and
showing a similar behavior to
K\"ahler manifolds. In particular, several relations among the Laplacians, the
spaces of harmonic forms and the associated cohomology groups, together with
Hard Lefschetz properties, are proved. Moreover, we show that for a compact HKT
-manifold the differential graded algebra
is formal and this will lead to an obstruction for
the existence of an HKT -structure
on a compact complex manifold . Finally, balanced HKT structures on
solvmanifolds are studied.Comment: 17 pages. Comments are welcom
Adjoint Monte Carlo Simulation of Fusion Product Activation Probe Experiment in ASDEX Upgrade tokamak
The activation probe is a robust tool to measure flux of fusion products from
a magnetically confined plasma. A carefully chosen solid sample is exposed to
the flux, and the impinging ions transmute the material making it radioactive.
Ultra-low level gamma-ray spectroscopy is used post mortem to measure the
activity and, thus, the number of fusion products.
This contribution presents the numerical analysis of the first measurement in
the ASDEX Upgrade tokamak, which was also the first experiment to measure a
single discharge. The ASCOT suite of codes was used to perform adjoint/reverse
Monte Carlo calculations of the fusion products. The analysis facilitates, for
the first time, a comparison of numerical and experimental values for
absolutely calibrated flux. The results agree to within a factor of about two,
which can be considered a quite good result considering the fact that all
features of the plasma cannot be accounted in the simulations.
Also an alternative to the present probe orientation was studied. The results
suggest that a better optimized orientation could measure the flux from a
significantly larger part of the plasma.Comment: Contribution in 1st EPS Conference on Plasma Diagnostics. First two
versions are for PoS(ECPD 2015)055. This 3rd version was accepted for
publishing in Journal of Instrumentatio
Complex Symplectic Lie Algebras with Large Abelian Subalgebras
We present two constructions of complex symplectic structures on Lie algebras
with large abelian ideals. In particular, we completely classify complex
symplectic structures on almost abelian Lie algebras. By considering compact
quotients of their corresponding connected, simply connected Lie groups we
obtain many examples of complex symplectic manifolds which do not carry
(hyper)k\"ahler metrics. We also produce examples of compact complex symplectic
manifolds endowed with a fibration whose fibers are Lagrangian tori.Comment: 33 pages, no figures. Comments are welcome
Third harmonic ICRF heating of Deuterium beam ions on ASDEX Upgrade
We report on recent experiments on the ASDEX Upgrade (AUG) tokamak (major radius R ≈1.65 m, minor radius a ≈ 0.5 m) with third harmonic ICRF heating of deuterium beam ions. Prior to this work, the scheme has been developed and applied on the JET tokamak, the largest currently operating tokamak (R ≈ 3 m, a ≈ 1 m), for fusion product studies and for testing alpha particle diagnostics in preparation of ITER [1]. The experiments reported here demonstrate that this scheme can also be used in medium size tokamaks such as AUG despite their
reduced fast ion confinement.This work has been carried out within the
framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.Postprint (published version
Bollettino Sismico Italiano: Analisys of Early Aftershocks of the 2016 MW 6.0 Amatrice, MW 5.9 Visso and MW 6.5 Norcia earthquakes in Central Italy
The Amatrice-Visso-Norcia seismic sequence is the most important of the last 30 years in Italy. The seismic sequence started on 24 August, 2016 and still is ongoing in central Apennines. At the end of February 2017 more than 57,000 events were located, 80,000 events up to the end of September 2017 (Fig. 1). The mainshocks of the sequence occurred on 24 August 2016 (Mw 6.0 and Mw 5.4), 26 October 2016 (Mw 5.4 and Mw 5.9), 30 October 2016 (Mw 6.5), 18 January 2017 (four earthquakes Mw≥ 5.0).
In this seismic sequence, all the waveforms recorded by temporary stations deployed by the SISMIKO emergency group (stations T12**; Moretti et al., 2016) where available in real- time at the surveillance room of INGV. Because of the high level of seismicity and the dense seismic network installed in the region, more than 150 events per day were located at the end of February 2017; still 60 events per day were located up to the end of August 2017.The Amatrice-Visso-Norcia is the most important seismic sequence since 2015, the time when the analysis procedures of the BSI group (Bollettino Sismico Italiano) were revised (Nardi et al., 2015). BSI is now available every four months on the web: bulletins contain revised earthquakes (location and magnitude) with ML≥ 1.5, quasi-real time revision of ML≥ 3.5 earthquakes and phase arrivals from waveforms recorded on seismic stations available from the European Integrated Data Archive (EIDA), (Mazza et al., 2012).
These last procedures allow the integration of signals from temporary seismic stations (Moretti et al., 2014) installed by the emergency group SISMIKO (Moretti and Sismiko working group, 2016), even when they are not in real time transmission, if they are rapidly archived in EIDA, together with real time signals from the seismic stations of the permanent INGV network.
The analysis strategy of the BSI group for the Amatrice -Visso - Norcia seismic sequence (AVN.s.s in the following) was to select the earthquakes located in the box with min/max latitude: 42.2/43.2 - and min/max longitude: 12.4/14.1 to prepare a special volume of BSI on the seismic sequence.PublishedTrieste, Italy1SR. TERREMOTI - Servizi e ricerca per la Societ
Bollettino Sismico Italiano gennaio – aprile 2019
Nel periodo che va dal 1 gennaio al 30 aprile 2019, gli analisti del BSI hanno revisionato tutti gli eventi di magnitudo M≥1.5, mentre i parametri dei terremoti di magnitudo inferiore a tale soglia di revisione sono stati calcolati in tempo reale, nella sala di sorveglianza sismica di Roma.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat
Bollettino Sismico Italiano settembre – dicembre 2018
Gli analisti del BSI hanno revisionato tutti gli eventi di magnitudo M≥1.5, localizzati dal 1 settembre al 31 dicembre 2018. I parametri dei terremoti di magnitudo inferiore a tale soglia di revisione, sono quelli calcolati in tempo reale, nella sala di sorveglianza sismica di Roma.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat
RAPPORTO BOLLETTINO SISMICO ITALIANO sulla revisione dei giorni 24-26 agosto; 26-27 ottobre; 30 ottobre-1 novembre 2016
La sequenza sismica Amatrice-Visso-Norcia (AVN s.s. nel seguito) include il terremoto più
forte avvenuto negli ultimi 30 anni in Italia ed è caratterizzata da molteplici eventi di
magnitudo superiore a 5.0. La sequenza sismica è iniziata il 24 agosto 2016 con due
terremoti di Mw 6.0 e Mw 5.4 nella zona di Amatrice (RI) ed è proseguita con altri due
terremoti forti avvenuti il 26 ottobre, Mw 5.4 e Mw 5.9 nell’area compresa tra i comuni di
Visso (MC), Castel S.Angelo sul Nera (MC), Norcia (PG) e Arquata del Tronto (AP). Il 30
ottobre si è verificato l’evento più forte della sequenza (Mw 6.5), con epicentro non
lontano da Norcia, che ha colpito un vasto settore dell'Italia centrale, interessando ben
quattro regioni (Umbria, Marche, Lazio e Abruzzo).Istituto Nazionale di Geofisica e VulcanologiaUnpublished1SR. TERREMOTI - Servizi e ricerca per la Societ
Bollettino Sismico Italiano settembre – dicembre 2017
I parametri dei terremoti registrati dalla Rete Sismica Nazionale Italiana, localizzati nelle sale di monitoraggio di Roma, di Napoli e di Catania sono immediatamente disponibili sul web, alla pagina http://terremoti.ingv.it/, e nell’Italian Seismological Instrumental and parametric Data-base (ISIDe working group (2016) version 1.0, DOI: 10.13127/ISIDe). Gli analisti del Bollettino Sismico Italiano (BSI) ricontrollano i parametri dei terremoti calcolati, inserendo pesi e polarità degli arrivi delle onde sismiche e integrando, inoltre, i dati letti in sala con tutti quelli disponibili nel sistema di acquisizione. Dal 1985 i dati del bollettino sono consultabili nel data-base ISIDe.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat