Precipitation of radiation belt electrons by magnetospherically reflected whistlers

We use a test particle simulation model based on gyro-averaged equations of motion to study the influence of oblique magnetospherically reflected (MR) whistlers on the near-loss-cone distribution function of radiation belt electrons. We find that MR whistlers originating in lightning can resonantly interact with radiation belt electrons over a broad range of L shells and precipitate higher energy electrons from lower L Shells. Electrons in the energy-range of 1 to 2.6 MeV are precipitated from L = 2, whereas from L = 4 the precipitated electron energy range is 150-220 keV. The precipitated differential electron flux, due to this interaction, is higher for higher L shells, and the maximum value ranges from Phi E-prec(1.11 MeV) 5.2 x 10(-4) electrons cm(-2) s(-1) keV(-1) at L = 2 to Phi E-prec(173 keV) = 4.6 x 10(-1) electrons cm(-2) s(-1) keV(-1) at L = 4. The lifetimes of radiation belt electrons in a given magnetic flux tube around the L shell on which the interaction takes place are found to be of the order of several days, comparable to lifetimes corresponding to electron loss induced by hiss, which was heretofore assumed to be the dominant loss mechanism [Lyons et al., 1972]. The minimum electron lifetimes vary from 2.4 days for 1.11 MeV electrons at L = 2 to 4.6 days for 173 keV electrons at L = 4

Magnetar outbursts: an observational review

Transient outbursts from magnetars have shown to be a key property of their emission, and one of the main way to discover new sources of this class. From the discovery of the first transient event around 2003, we now count about a dozen of outbursts, which increased the number of these strongly magnetic neutron stars by a third in six years. Magnetar outbursts might involve their multi-band emission resulting in an increased activity from radio to hard X-ray, usually with a soft X-ray flux increasing by a factor of 10-1000 with respect to the quiescent level. A connected X-ray spectral evolution is also often observed, with a spectral softening during the outburst decay. The flux decay times vary a lot from source to source, ranging from a few weeks to several years, as also the decay law which can be exponential-like, a power-law or even multiple power-laws can be required to model the flux decrease. We review here on the latest observational results on the multi-band emission of magnetars, and summarize one by one all the transient events which could be studied to date from these sources.Comment: 34 pages, 6 figures. Chapter of the Springer Book ASSP 7395 "High-energy emission from pulsars and their systems", proceeding of the Sant Cugat Forum on Astrophysics (12-16 April 2010). Review updated to January 201

Strongly magnetized pulsars: explosive events and evolution

Well before the radio discovery of pulsars offered the first observational confirmation for their existence (Hewish et al., 1968), it had been suggested that neutron stars might be endowed with very strong magnetic fields of $10^{10}$-$10^{14}$G (Hoyle et al., 1964; Pacini, 1967). It is because of their magnetic fields that these otherwise small ed inert, cooling dead stars emit radio pulses and shine in various part of the electromagnetic spectrum. But the presence of a strong magnetic field has more subtle and sometimes dramatic consequences: In the last decades of observations indeed, evidence mounted that it is likely the magnetic field that makes of an isolated neutron star what it is among the different observational manifestations in which they come. The contribution of the magnetic field to the energy budget of the neutron star can be comparable or even exceed the available kinetic energy. The most magnetised neutron stars in particular, the magnetars, exhibit an amazing assortment of explosive events, underlining the importance of their magnetic field in their lives. In this chapter we review the recent observational and theoretical achievements, which not only confirmed the importance of the magnetic field in the evolution of neutron stars, but also provide a promising unification scheme for the different observational manifestations in which they appear. We focus on the role of their magnetic field as an energy source behind their persistent emission, but also its critical role in explosive events.Comment: Review commissioned for publication in the White Book of "NewCompStar" European COST Action MP1304, 43 pages, 8 figure

The intensification of metallic layered phenomena above thunderstorms through the modulation of atmospheric tides

We present a multi-instrument experiment to study the effects of tropospheric thunderstorms on the mesopause region and the lower ionosphere. Sodium (Na) lidar and ionospheric observations by two digital ionospheric sounders are used to study the variation in the neutral metal atoms and metallic ions above thunderstorms. An enhanced ionospheric sporadic E layer with a downward tidal phase is observed followed by a subsequent intensification of neutral Na number density with an increase of 600 cm−3 in the mesosphere. In addition, the Na neutral chemistry and ion-molecule chemistry are considered in a Na chemistry model to simulate the dynamical and chemical coupling processes in the mesosphere and ionosphere above thunderstorms. The enhanced Na layer in the simulation obtained by using the ionospheric observation as input is in agreement with the Na lidar observation. We find that the intensification of metallic layered phenomena above thunderstorms is associated with the atmospheric tides, as a result of the troposphere-mesosphere-ionosphere coupling

Coarctation of the Aorta Associated with Left Subclavian Artery Aneurysm: A Case Report

Aneurysm of the left subclavian artery (LSA) in association with coarctation of the aorta (CoAo) is a rare phenomenon, especially in the younger population. A 19-year-old male patient was admitted for lower extremity varices and diagnosed to have severe CoAo and a 45-mm LSA aneurysm after digital subtraction angiography following detection of non-palpable lower extremity pulses on physical examination. Corrective surgery was performed from a left posterolateral thoracotomy through the 4th intercostal space, and a discrete ring-like coarctation tissue was observed in the aorta just below the level of the LSA orifce. Complete excision of the coarctation tissue was followed by aortoplasty with a Dacron patch. Additionally, the subclavian aneurysm was completely excised and a 10-mm Dacron tube graft interposition was performed. Prompt diagnosis and surgical treatment in particularly hypertensive patients precludes significant mortality and morbidity following a possible rupture

An alternative patch repair technique during valve replacement for native valve endocarditis

A patient with native valve endocarditis and vegetation on anterior mitral leaflet underwent aortic valve replacement with preservation of aortic noncoronary leaflet as a patch over the inflammated intervalvular fibrous body. This technique may minimize prosthetic material use, which is the most important risk factor for reinfection

Výdeoendoscopýc retroperýtoneal lumbar sympathectomy for selected cases: a new technýque

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