Abstract We report the overdense electron acceleration and dense gamma ray emission via use of two continuous laser pulses irradiating near critical density plasma. Thanks to ion channel formed behind first pulse, leading beam is well focused a higher intensity. As result, noticeable re-injection focusing when one incident significantly suppressed in two-consecutive- lasers scheme, efficiently ...

The intergalactic medium at redshifts 2–6 can be studied observationally through the absorption features it produces in the spectra of background quasars. Most of the UV-absorption lines arise in mildly overdense regions, which can be simulated reliably with current hydrodynamical simulations. Comparison of observed and simulated spectra allows one to put contraints on the model’s parameters.

We consider the effect of reionization on the clustering properties of galaxy samples at intermediate redshifts (z ∼ 0.3–5.5). Current models for the reionization of intergalactic hydrogen predict that overdense regions will be reionized early, thus delaying the build up of stellar mass in the progenitors of massive lower-redshift galaxies. As a result, the stellar populations observed in inter...

The high-β spherical tokamaks (ST), such as NSTX and MAST, are attractive fusion devices for studying the physics of current drive by electron cyclotron (EC) waves. While ST plasmas are overdense to conventional EC waves, electron Bernstein waves (EBW) can be used to generate plasma currents. Besides providing better confinement, EBW driven current can also help suppress neoclassical tearing mo...

Context. During the 14th/15th of April 2002, several flares occurred in NOAA active region complex 9893/9910. Two of these were previously interpreted as having anomalously high coronal column densities. Aims. We develop a scenario using multiwavelength observations to explain the high coronal column density (≈1020 cm−2) present at the onset of the 14th April 2002 M3.7 hard X-ray event. Methods...