Richard John Hutcheon

• Keele University

Context. The Kepler K2 mission now makes it possible to find and study a wider variety of eclipsing binary stars than has been possible to-date, particularly long-period systems with narrow eclipses. Aims. Our aim is to characterise eclipsing binary stars observed by the Kepler K2 mission with orbital periods longer than P ≈ 5.5 days. Methods. The...

The Kepler K2 mission now makes it possible to find and study a wider variety of eclipsing binary stars than has been possible to-date, particularly long-period systems with narrow eclipses. Our aim is to characterise eclipsing binary stars observed by the Kepler K2 mission with orbital periods longer than $P\approx 5.5$ days. The $ellc$ binary sta...

V1094 Tau is bright eclipsing binary star with an orbital period close to 9 days containing two stars similar to the Sun. Our aim is to test models of Sun-like stars using precise and accurate mass and radius measurements for both stars in V1094 Tau. We present new spectroscopy of V1094 Tau which we use to estimate the effective temperatures of bot...

Ionisation potentials are derived for the neon-like ions of Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, and Y by applying the Ritz law to observed wavelengths in one or both of the 2p6 1So-2p5nd 1P1, 3D1 Rydberg series. The wavelengths are adjusted to allow for mutual and configuration interaction. The potential of neon-like Ar IX is determined fro...

The L-shell soft-X-ray emission spectra of Cu, Zn, Ga, As, Br, Rb and Sr from laser-produced plasma sources were recorded with a convex-crystal spectrograph. The spectrograms were measured to provide wavelengths accurate to ± 2 mÅ for neon-like and 2p5-2p43s, 3d fluorine-like transitions. Theoretical wavelengths and oscillator strengths were comput...

Optical parametric oscillators (OPOs) using zinc germanium phosphide (ZGP) crystals as the active non-linear medium are important devices for wavelength conversion into the 3 to 5 mum mid-infrared waveband. However, the presence of optical absorption within ZGP at the pump wavelength can lead to detrimental thermo-optic effects (thermal lensing and...

The Stark broadened profiles of the Lyman, Balmer and Paschen lines of neutral hydrogen have been calculated from the line center to the line wings. The Model Microfield method has been used for both the electron and ion contributions. The no quenching and the dipolar approximations have been used. The plasma is assumed to be composed of electrons...

Neodymium glass laser pulses of up to 2 GW power, 10 ns duration and focused flux densities up to 2*1013 W cm-2 have been used to form plasmas at temperatures up to 450 eV. Plane solid plastic targets with atoms of hydrogen, nitrogen, carbon, oxygen and fluorine were used. The relation between laser flux density and electron temperature was studied...

The collisional-radiative model for the distribution of population densities among the energy states of a hydrogen-like ion plasma has been extended to lower electron densities by including the additional atomic processes of two-photon decay of the 2S level and electron- and proton-induced transitions between the component angular momentum sublevel...

The application of a convex mica crystal spectrometer to soft X-ray spectroscopy of laser-produced plasmas is discussed. Photographic spectra were obtained with resolving power 1500 and show isoelectronic scaling of oxygen-, nitrogen- and neon-like ion spectra of copper, zinc and gallium in the spectral region 8-13 AA. Photoelectric continuum measu...

New tables of Stark broadened hydrogen Lyman, Balmer and Paschen lines are presented for a wide range of plasma conditions, allowing the complete spectrum of these series to be modelled up to the Inglis Teller limit. The formalism, based on the Model Microfield Method (MMM) for both the electronic and ionic broadenings, gives an accurate descriptio...

Wavelengths and oscillator strengths for the 2s22p5-2s22p44d, 4s electric-dipole transitions in fluorine-like ions from copper to arsenic have been calculated using Cowan and Griffin's HXR method (1970) and Slater-Condon theory (1978). Configuration mixing effects have been considered in detail. The predictions are compared with experimental spectr...

An x-ray imaging system with a bent focusing crystal was used for time-resolved one-dimensional imaging of a long plasma column of highly ionized aluminum. This scheme uses a focusing geometry with a spherically bent crystal and a slit on the Rowland circle. Alternative schemes of x-ray monochromatic imaging are briefly discussed. The homogeneity o...

An X-ray imaging analyzer has been used to produce time-resolved one-dimensional images of long, highly-ionized aluminum plasma columns. Several imaging schemes are briefly discussed and the scheme adopted is based on a focusing Johann geometry with a spherically bent crystal and a slit on the Rowland circle. The homogeneity of laser-produced plasm...

A Coherent Anti-Stokes Raman Spectroscopy (CARS) study of the hydrogen plasma generated by a discharge with magnetic multipolar confinement has been conducted at pressures in the range 0.5-5 Pa. The steady-state radial distribution of the rovibrational populations has been measured. The vibrational temperature is always uniformly distributed and so...

The physics of laser-produced plasmas (LPPs) is now a subject of international research on a large scale. This chapter discusses the spectroscopy of LPPs. The connection between spectroscopy and plasma physics is generally strong, as spectroscopy is a powerful plasma diagnostic technique and plasmas provide novel spectroscopic sources. LPPs are no...

In this paper a description is given of a collisional-radiative calculation for hydrogen-like ions of nuclear charge less than about 15. Separate account is taken of the (n, l, j) sublevels up to and including n = 4 so that the results of the calculation may be used to predict the intensities of the fine-structure components of the corresponding tr...

A record of the coronal X-ray emission spectrum between 13.3 and 13.8 A is presented which was obtained with a rocketborne scanning Bragg monochromator. Identification of lines due to the Fe XIX 2p-3d transition array is discussed, and four features still unidentified are noted. Blending of Fe XIX lines in the long-wavelength wing of the Ne IX 13.4...

According to Parker's earlier articles in this journal the photospheric temperature is lower in sunspots than elsewhere because of increased outflow of mechanical energy, rather than inhibited inflow from the convective zone. In this case the atmosphere above the spot group receives an excess supply of energy that must equal the deficiency in radia...

Knowledge of the (differential) emission measure function (with temperature), Y(Te), is likely to be of fundamental significance in attempts to understand the behaviour of any optically thin plasma - and this is certainly true of present studies of the solar atmosphere. In this latter case the gross temperature structure of material below 10 ⁶ K ha...

The L-shell spectra of heavy elements from germanium to molybdenum have been observed in plasmas generated by high power neodymium lasers at Queens University, Belfast and the Central Laser Facility (Rutherford Laboratory). The spectra were recorded with convex crystal spectrometers with either a mica crystal (radius of curvature 3.81 cm) or a PET...

The wavelengths and intensities of the stronger transitions in the spectrum of Ni xix are reduced from measurements of the X-ray spectra of three coronal active regions. The new measured wavelengths are consistent with prediction by isoelectronic extrapolation from the wavelengths of well established transitions but are about 0.01 longer than previ...

X-ray emission spectra of coronal active regions have been studied for several years by use of Skylark rocket vehicles equipped with a Bragg spectrometer. Many new emission lines have been used for diagnosis of the condition of the coronal plasma and for determination of ionic term diagrams. This paper gives an account of the behavior, during opera...

The wavelengths and intensities of n = 3-2 and n = 4-2 transitions in Fe XVII are reduced from meaurements of the X-ray spectra of three coronal active regions. The observations were made using Bragg X-ray spectrometers operated on two Skylark rocket vehicles. New wavelength measurements are given with an uncertainty of + or - 0.003 A. Relative int...

Wavelengths and relative intensities are calculated for previously unknown higher members of all Rydberg series of Fe XVII known to be significantly radiated by coronal active regions. High-resolution coronal-active-region X-ray-spectrum measurements are analyzed to find these transitions. The measured wavelengths and intensities are given along wi...

This summary reports new emission lines of Fe xvii observed in two coronal active regions (McMath regions 12624, 12628). The lines were recorded by a Bragg plane crystal spectrometer collimated to 3′ FWHM, with a gypsum crystal scanning the wavelength range 8–14 Å. This spectrometer, part of a three spectrometer package previously used by Parkinson...

This paper describes the analysis of soft X-ray spectra of solar active regions observed on a Skylark sounding rocket flight. The experiment was launched from Woomera, South Australia, at 0535 UT on 26th November 1973. The payload consisted of 3 plane scanning Bragg crystal spectrometers, covering the wavelength range 4 to 23 Å, and collimated to 3...

Summary This summary reports new emission lines of Fe XVII observed in two coronal active regions (McMath regions 12624, 12628). The lines were recorded by a Bragg plane crystal spectrometer collimated to 3′ FWHM, with a gypsum crystal scanning the wavelength range 8–14 Å. This spectrometer, part of a three spectrometer package previously used by P...

Summary This paper describes the analysis of soft X-ray spectra of solar active regions observed on a Skylark sounding rocket flight. The experiment was launched from Woomera, South Australia, at 0535 UT on 26th November 1973. The payload consisted of 3 plane scanning Bragg crystal spectrometers, covering the wavelength range 4 to 23 Å, and collima...

New transitions, belonging to the series 2p1P-nd1D, 2s3S-np3P and 2p3D, are reported in the spectrum of helium-like fluorine (F VIII).

Laser produced plasmas are a useful source of highly stripped ions for XUV spectroscopy and it is therefore important to understand the relation between the incident laser flux, plasma temperature and ionisation equilibrium.

Laser produced plasmas are a useful source of highly stripped ions for XUV spectroscopy and it is therefore important to understand the relation between the incident laser flux, plasma temperature and ionisation equilibrium.

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