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Recent observations of the fast time variability in the hard X-ray emission from solar flares are interpreted. The fast spikes are assumed to be superimposed on the thermal X-ray emission. The rise and fall of a spike are caused by disruptions in the plasma. The rise time represents the impulsive heating time and the decay or fall time represents a quick cooling of the plasma due to the accelerating growth rate of the m=1 tearing mode. The estimated characteristic time durations of the spike are found to be in good agreement with the observed ones.
There is a need for clinical tools to identify cultural issues in diagnostic assessment.
To assess the feasibility, acceptability and clinical utility of the DSM-5 Cultural Formulation Interview (CFI) in routine clinical practice.
Mixed-methods evaluation of field trial data from six countries. The CFI was administered to diagnostically diverse psychiatric out-patients during a diagnostic interview. In post-evaluation sessions, patients and clinicians completed debriefing qualitative interviews and Likert-scale questionnaires. The duration of CFI administration and the full diagnostic session were monitored.
Mixed-methods data from 318 patients and 75 clinicians found the CFI feasible, acceptable and useful. Clinician feasibility ratings were significantly lower than patient ratings and other clinician-assessed outcomes. After administering one CFI, however, clinician feasibility ratings improved significantly and subsequent interviews required less time.
The CFI was included in DSM-5 as a feasible, acceptable and useful cultural assessment tool.
Self-organization i.e. the formation of large ordered structures in a turbulent medium is a consequence of inverse cascade where energy preferentially transfers towards large spatial scales. It is envisaged that this may be one way of explaining solar granulation at various scales.
We study Parametric Decay Instabilities(PDI) using the kinetic description, in the homogeneous and unmagnetized plasmas. These instabilities cause anomalous absorption of the incident electromagnetic (e.m)radiation. The maximum plasma temperatures reached are functions of luminosity of the non-thermal radio radiation and the plasma parameters.
Abstract Non-linear interactions between small fluid elements, magnetized or otherwise, in an energetically open nonlinear system facilitate the formation of large coherent stable structures. This is knwon as self-organization. We interpret solar granulation on all scales and the formation and evolution of some structures in solar active regions to be the result of self-organization processes occuring in a turbulent medium.
Stimulated Raman scattering (SRS) processes offer an attractive and efficient method for producing both essentially the entire non-thermal continuum as well as fast electrons in active galactic nuclei (AGN). In this picture, electrons are accelerated by Langmuir waves which are generated by Raman forward scattering (RFS); these electrons then rapidly radiate their energy by means of Raman back scattering (RBS) off of spatially periodic magnetic fields. Such periodic fields can be produced by magnetic modulational instabilities of the Langmuir field The emission is envisaged to arise from an expanding region, with the highest frequency radiation originating from the smallest volumes at the core of the AGN. Time variability is dominated by density fluctuations in these magnetohydrodynamic flows.
The square of the four-momentum of a photon in vacuum is zero. However, in an unmagnetized plasma, it is equal to the square of the plasma frequency. Further, the electron-photon coupling vertex is modified in a plasma to include the effect of the plasma medium. I calculate the cross sections of three processes in a plasma—Compton scattering and electron-positron pair annihilation and production. At high plasma densities, the cross sections are found to change significantly. Such high plasma densities exist in several astrophysical sources.
In preparing the present report, which covers the period July 1, 1984, to June 30, 1987, close collaboration has taken place between Commission 10 and 12, the two solar commissions, in order to avoid duplications and to insure that pertinent subjects are treated. The reader is referred to the report of Commission 12 for further solar topics. The proceedings are found at the beginning of the references for each section, followed by the usual alphabetical listing. In some sections this listing refers to the previous proceedings by their numbers; in others we retain the conventional reference. It is a pleasure to acknowledge the excellent work of the reviewers who wrote the different sections of this report, and all the members of the commission who provided information on research to be included.
It is suggested that inverse cascade that may occur in the turbulent cosmic medium can result in the formation of very large scale structures in the universe, upto the largest scales like the Great Wall. Again clustering of galaxies on all scales is interpreted to be due to these self-organisation processes occurring in a turbulent medium, the largest structures being anisotropic and nearly two dimensional, the smaller structures remaining isotropic. The observed fractal distribution of galaxies is also interpreted on this basis. The direct proportionality between the flow velocity and the linear dimension of the structure may show a way out of the dilemma of missing matter.
We study the complexity of supergranular cells using the intensity patterns obtained at the Kodaikanal solar observatory during the solar maximum. Our data consists of visually identified supergranular cells, from which a fractal dimension D is obtained according to the relation P ∝ AD/2 where A is the area and P is the perimeter of the cells. We find a difference in the fractal dimension between the active and the quiet region cells which is conjectured to be due to the magnetic activity level.
Montgomery and co-workers have developed a framework to describe the steady state of a turbulent magnetofluid, without the usual recourse to linearization. Thus the magnetic and velocity fields emerge in their fully nonlinear form as a consequence of the selective decays of the invariants of the system. Using this statistical theory of magnetohydrodynamic turbulence, the pressure, magnetic and flow fields of a solar coronal loop have been determined. The spatial and time profiles of the loop pressure are derived. A comparison with the observed properties of the loops is made, whenever possible.
It is shown that the exact nonlinear solution for the Hall–Alfvén waves can be obtained in a uniformly rotating weakly ionized plasma such as those which exist in various types of accretion disks. In addition this piece of work demonstrates a method of eliminating the inaccuracies embedded in the literature on this subject.