46 research outputs found
Heating the Solar Atmosphere by the Self-Enhanced Thermal Waves Caused by the Dynamo Processes
We discuss a possible mechanism for heating the solar atmosphere by the
ensemble of thermal waves, generated by the photospheric dynamo and propagating
upwards with increasing magnitudes. These waves are self-sustained and
amplified due to the specific dependence of the efficiency of heat release by
Ohmic dissipation on the ratio of the collisional to gyro- frequencies, which
in its turn is determined by the temperature profile formed in the wave. In the
case of sufficiently strong driving, such a mechanism can increase the plasma
temperature by a few times, i.e. it may be responsible for heating the
chromosphere and the base of the transition region.Comment: v2: A number of minor corrections and additional explanations.
AASTeX, 5 pages, 2 EPS figures, submitted to The Astrophysical Journa
Interference of Fano-Rashba conductance dips
We study the interference of two tunable Rashba regions in a quantum wire
with one propagating mode. The transmission dips (Fano-Rashba dips) of the two
regions either cross or anti cross depending on the distance between the two
regions. For large separations we find Fabry-P\'erot oscillations due to the
interference of forwards and backwards propagating modes. At small separations
overlapping evanescent modes play a prominent role, leading to an enhanced
transmission and destroying the conductance dip. Analytical expressions in
scattering-matrix theory are given and the relevance of the interference effect
in a device is discussed.Comment: 10 pages, 4 embedded figure
Correlation functions of eigenvalues of multi-matrix models, and the limit of a time dependent matrix
We consider the correlation functions of eigenvalues of a unidimensional
chain of large random hermitian matrices. An asymptotic expression of the
orthogonal polynomials allows to find new results for the correlations of
eigenvalues of different matrices of the chain. Eventually, we consider the
limit of the infinite chain of matrices, which can be interpreted as a time
dependent one-matrix model, and give the correlation functions of eigenvalues
at different times.Comment: Tex-Harvmac, 27 pages, submitted to Journ. Phys.