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Past experiments [S. Depierreux et al., Phys. Rev. Lett. 102, 195005 (2009)10.1103/PhysRevLett.102.195005] have exhibited the plasma-induced incoherence (PII) process and the reduced imprint in the multikilojoule regime when a thin low-density foam is disposed in front of a solid target. Complementary experiments have been designed to analyze the mechanisms involved, the important parameters, and the role of the optical smoothing in the case of the laser megajoule. Forward stimulated Brillouin scattering (FSBS) is identified as the dominant mechanism governing the angular spray of the laser. FSBS also increases the laser bandwidth and imparts levels of temporal and spatial incoherencies beyond the present capacities of the optical smoothing of the megajoule laser facilities. Such a PII beam becomes suitable to achieve the high degree of irradiation uniformity required to experiment high-convergence efficient direct-drive inertial confinement fusion configurations at the megajoule scale which would otherwise require major changes in the laser chains. By reducing backscattering losses and/or allowing less optically applied smoothing, PII could relax the constraints imposed on the laser system and open the road to an increase in the energy coupled to the target in indirect-drive experiments.

We propose a semi-analytical modeling of smoothed laser beam deviation induced by plasma flows. Based on a Gaussian description of speckles, the model includes spatial, temporal, and polarization smoothing techniques, through fits coming from hydrodynamic simulations with a paraxial description of electromagnetic waves. This beam bending model is then incorporated into a ray tracing algorithm and carefully validated. When applied as a post-process to the propagation of the inner cone in a full-scale simulation of a National Ignition Facility (NIF) experiment, the beam bending along the path of the laser affects the refraction conditions inside the hohlraum and the energy deposition, and could explain some anomalous refraction measurements, namely, the so-called glint observed in some NIF experiments.

The mechanisms of laser imprint reduction on a surface of a planar foil performed using an underdense foam are presented. The consequences on the Rayleigh–Taylor instability growth at the ablation front when the foil is accelerated are studied. The analysis is based on numerical simulations using a chain of codes: the electromagnetic paraxial code Parax provides the modifications of the intensity perturbation spectrum while the laser beam is crossing the foam. Two-dimensional axially symmetric simulations with the radiation hydrodynamic code CHIC describe the foam expansion and the foil dynamics. Finally, the perturbed flow calculations and the instability growth are investigated with the two-dimensional CHIC version in the planar geometry by using the initial and smoothed perturbation spectra. The dominant role of temporal laser smoothing during the time of foam crossing by the laser beam is demonstrated. Applications to the direct drive targets for inertial confinement fusion are discussed.

We describe two new cases of Rosai-Dorfman disease with intrascrotal involvement. Also known as sinus histiocytosis with massive lymphadenopathy, this is a rare entity, usually presenting with massive bilateral cervical lymphadenopathy. It is associated with extranodal involvement in up to 40% of cases, commonly in the face and neck area. Isolated intrascrotal involvement with no lymphadenopathies is extremely rare, and its definitive diagnosis is histopathological. Although they are the most frequent type, not all intrascrotal lesions are neoplastic; therefore, it is important to know other possible etiologies and their radiogical features that might help in the diagnosis. We also review other cases of intrascrotal involvement reported in the literature, as well as a review clinical features, treatment and prognosis of this entity, and a differential diagnosis of solid intrascrotal lesions., (© 2015 The Japanese Urological Association.)

This Letter presents first experimental results of the laser imprint reduction in fusion scale plasmas using a low-density foam layer. The experiments were conducted on the LIL facility at the energy level of 12 kJ with millimeter-size plasmas, reproducing the conditions of the initial interaction phase in the direct-drive scheme. The results include the generation of a supersonic ionization wave in the foam and the reduction of the initial laser fluctuations after propagation through 500 mum of foam with limited levels of stimulated Brillouin and Raman scattering. The smoothing mechanisms are analyzed and explained.

A statistical model for forward stimulated-Brillouin scattering is developed for a spatially incoherent, monochromatic, laser beam propagating in a plasma. The threshold above which the laser beam spatial incoherence cannot prevent the coherent growth of forward stimulated-Brillouin scattering is computed. It is found to be well below the threshold for self-focusing. Three-dimensional simulations confirm its existence and reveal the onset of beam spray above it. From these results, we propose a new figure of merit for the control of propagation through a plasma of a spatially incoherent laser beam.

Objective: To show the characteristic findings of testicular ultrasound and MR imaging in patients with congenital adrenal hyperplasia and testicular adrenal remnants., Methods/results: Male patient with congenital adrenal hyperplasia presenting with azoospermia. Testicular ultrasound showed heteroecogenic nodular lesions in both testicles. In view of the past medical history of the patient suspect of adrenal tissue remnants was raised. Testicular MRI findings supported the diagnosis. Regression of the intratesticular masses after glucocorticosteroid treatment confirmed the disease., Conclusions: The presence of a testicular mass in a patient with congenital adrenal hyperplasia may pose a diagnostic dilemma in relation to perform or not testicular biopsy or orchIectomy to identify it. The combination of imaging diagnostic tests such as testicular ultrasound and MRI, the medical history of congenital adrenal hyperplasia and the regression of the lesions after administration of glucocorticosteroids allow to identify this pathologic entity without performance of other invasive procedures.

Objective: To determine the diagnostic usefulness of MRI in the diagnosis of Leydig cell testicular tumor., Methods/results: Male patient consulting for infertility. Testicular ultrasound and MRI were performed. Testicular MRI showed a hypointense lesion in T2 powered sequences with intense, homogeneous enhance after contrast administration., Conclusions: MRI is considered an excellent diagnostic test for the management of patients with testicular diseases of difficult diagnosis on ultrasound, contributing to define the lesion, a Leydig cell testicular tumor in this case.

A strong reduction of the spatial coherence of a laser beam after its propagation through a plasma has been measured using a Fresnel biprism interferometer. The laser beam was diffraction limited; the coherence width was reduced from 40 mm in vacuum down to a few mm with the plasma. Numerical results based on a paraxial model exhibit a coherence degree close to the experimental one; they also prove the importance of taking into account the nonlocal transport effects in numerical simulations for such plasma conditions.

Before of the implantation of ultrasound there were few cases of ovarian cysts reported in literature because only the very large ones or those which result in mechanical complications produce symptoms. The authors report 17 cases of neonatal ovarian cysts diagnosed by prenatal ultrasound. All of the infants were asymptomatic after birth despite their size or being twisted. The diameter of the cysts varied from 2.5 to 10 cm. Five neonates were treated conservatively and the cysts resolved spontaneously. 12 infants underwent surgery following postnatal confirmation, 9 of these patients had complex ovarian cysts and at laparotomy all of them had torsion of the ovary, three of them were autoamputated, and 3 uncomplicated cysts because their large size or their association to a nephroblastoma. Simple cysts of the ovary tend to resolve spontaneously and therefore, must be treated conservatively. Complex cysts or simple ones larger than 4 cm that do not disappear should undergo surgical removal.