R. G. L. Vann R. O. Dendy G. Rowlands T. D. Arber N. D’Ambrumenil
The Berk–Breizman augmentation of the Vlasov–Maxwell system is widely used to model self-consistent resonant excitation and damping of wave fields by evolving energetic particle populations in magnetic fusion plasmas. The key model parameters are the particle annihilation rate, which drives bump-on-tail structure, and the linear wave damping ra…
PublishedJ. Greenhough S.C. Chapman R.O. Dendy V.M. Nakariakov G. Rowlands
We investigate the distribution of fluctuations in solar irradiance when integrated over the full disk, obtained using extreme ultraviolet / soft X-ray observations from the SOHO CELIAS / SEM instrument. This time series sums over both the contributions of single distinguishable flares, and of many other processes. By detrending we select events wi…
PublishedJ. Greenhough S.C. Chapman S. Chaty R.O. Dendy G. Rowlands
Whilst direct observations of internal transport in accretion disks are not yet possible, measurement of the energy emitted from accreting astrophysical systems can provide useful information on the physical mechanisms at work. Here we examine the unbroken multi-year time variation of the total X-ray flux from three sources: Cygnus X-1, the microqu…
PublishedS. C. Chapman R. O. Dendy G. Rowlands
There is increasing evidence that the Earth’s magnetosphere, like other macroscopic confined plasma systems (magnetic fusion plasmas, astrophysical accretion discs), displays sandpile-type phenomenology so that energy dissipation is by means of avalanches which do not have an intrinsic scale. This may in turn imply that these systems evolve via s…
PublishedP. Helander S. C. Chapman R. O. Dendy G. Rowlands N. W. Watkins
A simple one-dimensional sandpile model is constructed which possesses exact analytical solvability while displaying both scale-free behavior and fractal properties. The sandpile grows by avalanching on all scales, yet its shape and energy content are described by a simple, continuous (but nowhere differentiable) analytical formula. The avalanche e…
Published