Collisionally excited X-ray laser schemes: progress at Rutherford Appleton Laboratory (Invited Paper)

1992 ◽  
Author(s):  
Ciaran L. S. Lewis ◽  
Domhnail O'Neill ◽  
David Neely ◽  
James O. Uhomoibhi ◽  
Ronald E. Burge ◽  
...  
Keyword(s):  
Rutherford Appleton Laboratory ◽  
X Ray

STUDY OF X-RAY LASER SCHEMES USING NEW EXPERIMENTAL FACILITIES AT THE RUTHERFORD APPLETON LABORATORY

1986 ◽  
Vol 47 (C6) ◽  
pp. C6-71-C6-79 ◽  
Author(s):  
M. H. KEY ◽  
J. E. BOON ◽  
C. BROWN ◽  
C. CHENAIS-POPOVICS ◽  
R. CORBETT ◽  
...  
Keyword(s):  
Rutherford Appleton Laboratory ◽  
X Ray ◽  
Experimental Facilities

scholarly journals A review of X-ray laser development at Rutherford Appleton Laboratory

2002 ◽  
Vol 20 (2) ◽  
pp. 201-209 ◽  
Author(s):  
G.J. TALLENTS ◽  
Y. ABOU-ALI ◽  
M. EDWARDS ◽  
R. KING ◽  
G.J. PERT ◽  
...  
Keyword(s):  
Optical Pumping ◽  
Laser Pulses ◽  
Travelling Wave ◽  
Picosecond Pulse ◽  
Speed Of Light ◽  
Rutherford Appleton Laboratory ◽  
Picosecond Pulses ◽  
X Ray ◽  
Laser Development ◽  
Preformed Plasma

Recent experiments undertaken at the Rutherford Appleton Laboratory to produce X-ray lasing over the 5–30 nm wavelength range are reviewed. The efficiency of lasing is optimized when the main pumping pulse interacts with a preformed plasma. Experiments using double 75-ps pulses and picosecond pulses superimposed on 300-ps background pulses are described. The use of travelling wave pumping with the approximately picosecond pulse experiments is necessary as the gain duration becomes comparable to the time for the X-ray laser pulse to propagate along the target length. Results from a model taking account of laser saturation and deviations from the speed of light c of the travelling wave and X-ray laser group velocity are presented. We show that X-ray laser pulses as short as 2–3 ps can be produced with optical pumping pulses of ≈1-ps.

scholarly journals Recent experiments at the Rutherford Appleton Laboratory to study the laser driven compression of CH shell targets and the effects of increasing aspect ratio

1986 ◽  
Vol 4 (3-4) ◽  
pp. 573-576
Author(s):  
J. Corbett ◽  
C. L. S. Lewis ◽  
E. Robertson ◽  
S. Saadat ◽  
P. F. Cunningham ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Spatial Resolution ◽  
Systematic Study ◽  
Rutherford Appleton Laboratory ◽  
Density Profiles ◽  
X Ray ◽  
Preliminary Results ◽  
Aspect Ratios ◽  
Laser Facility

Recent experiments to study the laser driven compression of CH shell targets and the effects of increasing aspect ratio using x-ray shadowgraph techniques are described. This work has been carried out at the Rutherford Appleton Laboratory's Central Laser Facility with 12 beam, 0·53 μm, 1·0 ns irradiation. X-ray shadowgraphy techniques have been used with a frame time of ∼100ps and spatial resolution of 5 to lOμm to obtain density profiles for the compressed targets. A systematic study of 150–200 μm targets with aspect ratios from ∼7 to ∼20 has been performed. The x-ray shadowgraphy techniques used are described, results in the form of x-radiographs presented and a discussion of preliminary results given.

X-Ray Laser Research at the Rutherford Appleton Laboratory

1987 ◽  
Author(s):  
O. Willi ◽  
D. Bassett ◽  
C. Chenais-Popovics ◽  
R. Corbett ◽  
M. Grande ◽  
...  
Keyword(s):  
Rutherford Appleton Laboratory ◽  
X Ray

Status of soft X-ray laser research at the Rutherford-Appleton laboratory

1988 ◽  
Vol 30 (1) ◽  
pp. 35-44 ◽  
Author(s):  
C L S Lewis ◽  
R Corbett ◽  
D O'Neill ◽  
C Regan ◽  
S Saadat ◽  
...  
Keyword(s):  
Rutherford Appleton Laboratory ◽  
X Ray

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

Some Problems in Understanding the Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 1-9
Author(s):  
A. H. Gabriel
Keyword(s):  
Solar Corona ◽  
Solar Atmosphere ◽  
Theoretical Modelling ◽  
Total System ◽  
Major Advance ◽  
X Ray ◽  
Proper Perspective ◽  
Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

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