[Pathology of chronic obstructive pulmonary disease]

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disorder of the lung characterized by poorly reversible airflow limitation. It is not a unique disease entity but rather a complex of conditions which include emphysema, chronic bronchitis and, sometimes, asthma. Moreover, COPD is a progressive disease often associated with exacerbations. Cigarette smoking, which is the most important risk factor for the development of COPD, induces pathological changes involving lung parenchyma, peripheral airways and central airways. Since lung parenchyma and peripheral airways are the sites responsible for airflow limitation and central airways are the main site of mucus hypersecretion, pathological changes in these compartments may be relevant in the development of COPD

Resistive g-modes in a reversed field pinch plasma

First direct experimental evidence of high frequency, high toroidal mode number (n>20), magnetic fluctuations due to unstable resistive interchange modes (g-modes) resonant in the edge region of a reversed field pinch (RFP) plasma is presented. Experimental characterization of time and space periodicities of the modes is provided by means of highly resolved in-vessel edge and insertable magnetic diagnostics. It is found that the spectral mode properties are in good agreement with the predictions of the theoretical linear resistive magnetohydrodynamic stability analysis. A simple model is proposed for the observed saturation levels of the modes.Comment: Submitted to Physical Review Letter

Electromagnetic turbulent structures: A ubiquitous feature of the edge region of toroidal plasma configurations

Electromagnetic features of turbulent filaments, emerging from a turbulent plasma background, have been studied in four different magnetic configurations: the stellarator TJ-II, the Reversed Field Pinch RFX-mod, a device that can be operated also as a ohmic tokamak, and the Simple Magnetized Torus, TORPEX. By applying an analogous diagnostic concept in all cases, direct measurements of both field-aligned current density and vorticity were performed inside the filament. The inter-machine comparison reveals a clear dependence of the filament vorticity upon the local time-averaged E x B flow shear. Furthermore, a wide range of local beta was explored allowing concluding that this parameter plays a fundamental role in the appearance of filament electromagnetic features

Measurements of plasma potential and electron temperature by ball-pen probes in RFX-mod

The ball-pen probe (BPP) is an innovative electric probe for direct measurements of the plasma potential. This probe was developed in IPP Prague and it is based on the Katsumata probe concept. Combined measurements of the plasma potential by a BPP and floating potential by a Langmuir probe provide also the value of the electron temperature. First test of the BPP on the RFX-mod reversed field pinch in Padova has been performed in November 2006. The BPP head, made of boron nitride, is equipped with four graphite collectors, which are positioned at four different radial positions h inside four shafts hollow into the probe head. The radial profile of the plasma potential and also the electron temperature were measured.Кулеподібний зонд – новий тип зонду для прямих вимірюаннь потенціалу плазми. Цей зонд розроблено у ІТП, в Празі, та засновано на концепції зонду Катсумати. Комбіновані вимірювання плазмового потенцілу кулеподібним зондом та плаваючого потенціалу Ленгмюрівським зондом дають також величину електронної температури. Перші випробування зонду в пінчі з оберненим полем на RFX-mod у Падові було проведено у листопаді 2006 р. Головка зонда, вироблена з нітриду бора, була оснащена чотирма графітовими колекторами, які були розташовані в чотирьох радіальних положеннях h усередині чотирьох порожнистих циліндричних отворів в голівці зонда. Виміряно радіальний профіль потенціалу плазми й електронну температуру.Шароподобный зонд – новый тип зонда для прямых измерений потенциала плазмы. Данный зонд разработан в ИФП, в Праге, и основан на концепции зонда Катсуматы. Комбинированные измерения плазменного потенциала шароподобным зондом и плавающего потенциала Ленгмюровским зондом дают также величину электронной температуры. Первые испытания зонда в пинче с обращенным полем на RFX-mod в Падове проведены в ноябре 2006 г. Головка зонда, сделанная из нитрида бора, оснащалась четырьмя графитовыми коллекторами, которые размещались в четырех различных радиальных положениях h внутри четырех пустотелых цилиндрических отверстий в головке зонда. Измерены радиальный профиль потенциала плазмы и электронная температура