This article is devoted to solving the problem of the plasma temperature distribution along a magnetic tube, one end of which is in the chromosphere, while the other is in the corona. The plasma ...temperature dependences of the density, pressure, and velocity of plasma are determined for various velocities of the plasma flow, which are given at the lower boundary of the transition region. In the case where gravitation can be neglected, these dependences are derived in the analytical form. The existence of three velocity ranges is demonstrated, for which: (a) the excitation of shock waves in the transition region is possible, (b) the transition region can be considered in the classical collisional approximation, and (c) the plasma heating process is close to the
p
= const mode and the calculated hard ultraviolet radiation coincides well with modern satellite observations. Based on the obtained results, we concluded that generally in the presence of plasma flows, the quiet transition region between the corona and the chromosphere should be considered in the classical approximation of Coulomb collisions.
Microstructural features across different length scales have a profound influence on the coercivity of magnetic alloys. Whereas the role of homophase boundaries on the pinning of magnetic domain ...walls is well established, the influence of heterophase interfaces on domain wall motion is complex and poorly understood. Here, we use state-of-the-art electron microscopy techniques to show that the magnetization reversal process in an Al0.3CoFeNi magnetic complex concentrated alloy (CCA), which is responsible for its coercivity, changes dramatically from a nucleation-type mechanism in the FCC+L12 state of the CCA, with a domain wall width of 171 nm, to a pinning type mechanism in the microstructure with colonies of FCC/L12 nanorods embedded in a BCC/B2 matrix, with a domain wall width of 35 nm. Our work reveals that heterophase FCC/BCC interfaces have a much stronger effect on coercivity than isostructural chemically ordered/disordered interfaces and provides a powerful guide to the rational design of microstructure to tune magnetic properties in both complex concentrated alloys and conventional magnetic alloys.
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The most remote isotope from the proton dripline (by 4 atomic mass units) has been observed: K-31. It is unbound with respect to three-proton (3p) emission, and its decays have been detected in ...flight by measuring the trajectories of all decay products using microstrip detectors. The 3p emission processes have been studied by the means of angular correlations of S-28 + 3p and the respective decay vertices. The energies of the previously unknown ground and excited states of K-31 have been determined. This provides its 3p separation energy value S-3p of -4.6(2) MeV. Upper half-life limits of 10 ps of the observed K-31 states have been derived from distributions of the measured decay vertices.
The STAR Collaboration reports the first observation of exclusive rho(0) photoproduction, AuAu-->AuAurho(0), and rho(0) production accompanied by mutual nuclear Coulomb excitation, ...AuAu-->Au*Au*rho(0), in ultraperipheral heavy-ion collisions. The rho(0) have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at sqrts(NN)=130 GeV agree with theoretical predictions treating rho(0) production and Coulomb excitation as independent processes.
Prospects of experimental studies of argon and chlorine isotopes located far beyond the proton dripline are studied by using systematics and cluster models. The deviations from the widespread ...systematics observed in Cl-28,Cl-29 and Ar-29,Ar-30 have been theoretically substantiated, and analogous deviations have been predicted for the lighter chlorine and argon isotopes. The limits of nuclear structure existence are predicted for Ar and Cl isotopic chains, with Ar-26 and Cl-25 found to be the lightest sufficiently long-living nuclear systems. By simultaneous measurements of protons and gamma rays following decays of such systems as well as their beta-delayed emission, an interesting synergy effect may be achieved, which is demonstrated by the example of Cl-30 and Ar-31 ground-state studies. Such a synergy effect may be provided by the new EXPERT setup (EXotic Particle Emission and Radioactivity by Tracking) being operated inside the fragment separator and spectrometer facility at GSI, Darmstadt.
A soft photon calorimeter for the SVD-2 experiment Ardashev, E. N.; Britvich, G. I.; Vorobiev, A. P. ...
Instruments and experimental techniques (New York),
03/2015, Volume:
58, Issue:
2
Journal Article
Peer reviewed
The design of the soft photon calorimeter for the SVD-2 experiment is described. The aperture of the calorimeter is 210 × 210 mm. The first results of its testing in the course of data acquisition in ...the E-190 experiment at the U-70 accelerator of the Institute for High Energy Physics are presented.
Concept of a fast forward detector (FFD) developed as part of Multi-Purpose Detector (MPD) setup for future experiments with beams of nuclear collider NICA is described. The FFD is aimed at ...triggering nucleus-nucleus collisions at the center of the MPD setup and generating start pulse for TOF detector. Two units of the detector module were designed, produced, and tested with cosmic rays and proton beam. The time resolution obtained in the measurements is ∼30 ps (sigma). Results of simulation, prototype developing and experimental tests are discussed.
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