206 results on '"Noullez, A."'
Search Results
2. Negative magnetic eddy diffusivities from test-field method and multiscale stability theory
- Author
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Andrievsky, Alexander, Brandenburg, Axel, Noullez, Alain, and Zheligovsky, Vladislav
- Subjects
Physics - Fluid Dynamics ,Astrophysics - Solar and Stellar Astrophysics ,Nonlinear Sciences - Chaotic Dynamics - Abstract
The generation of large-scale magnetic field in the kinematic regime in the absence of an alpha-effect is investigated by following two different approaches, namely the test-field method and multiscale stability theory relying on the homogenisation technique. We show analytically that the former, applied for the evaluation of magnetic eddy diffusivities, yields results that fully agree with the latter. Our computations of the magnetic eddy diffusivity tensor for the specific instances of the parity-invariant flow-IV of G.O. Roberts and the modified Taylor-Green flow in a suitable range of parameter values confirm the findings of previous studies, and also explain some of their apparent contradictions. The two flows have large symmetry groups; this is used to considerably simplify the eddy diffusivity tensor. Finally, a new analytic result is presented: upon expressing the eddy diffusivity tensor in terms of solutions to auxiliary problems for the adjoint operator, we derive relations between magnetic eddy diffusivity tensors that arise for opposite small-scale flows v(x) and -v(x)., Comment: 29 pp., 19 figures, 42 references
- Published
- 2015
- Full Text
- View/download PDF
3. Scaling Laws of Turbulence and Heating of Fast SolarWind: The Role of Density Fluctuations
- Author
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Carbone, V., Marino, R., Sorriso-Valvo, L., Noullez, A., and Bruno, R.
- Subjects
Physics - Space Physics ,Physics - Fluid Dynamics ,Physics - Plasma Physics - Abstract
Incompressible and isotropic magnetohydrodynamic turbulence in plasms can be described by an exact relation for the energy flux through the scales. This Yaglom-like scaling law has been recently observed in the solar wind above the solar poles observed by the Ulysses spacecraft, where the turbulence is in an Alfv\'enic state. An analogous phenomenological scaling law, suitably modified to take into account compressible fluctuations, is observed more frequently in the same dataset. Large scale density fluctuations, despite their low amplitude, play thus a crucial role in the basic scaling properties of turbulence. The turbulent cascade rate in the compressive case can moreover supply the energy dissipation needed to account for the local heating of the non-adiabatic solar wind.
- Published
- 2010
- Full Text
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4. The evolution of anisotropic structures and turbulence in the multi-dimensional Burgers equation
- Author
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Gurbatov, S. N., Moshkov, A. Yu., and Noullez, A.
- Subjects
Nonlinear Sciences - Chaotic Dynamics - Abstract
The goal of the present paper is the investigation of the evolution of anisotropic regular structures and turbulence at large Reynolds number in the multi-dimensional Burgers equation. We show that we have local isotropization of the velocity and potential fields at small scale inside cellular zones. For periodic waves, we have simple decay inside of a frozen structure. The global structure at large times is determined by the initial correlations, and for short range correlated field, we have isotropization of turbulence. The other limit we consider is the final behavior of the field, when the processes of nonlinear and harmonic interactions are frozen, and the evolution of the field is determined only by the linear dissipation., Comment: 13 pages, 5 figures
- Published
- 2008
5. Observation of inertial energy cascade in interplanetary space plasma
- Author
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Sorriso-Valvo, Luca, Marino, Raffaele, Carbone, Vincenzo, Lepreti, Fabio, Veltri, Pierluigi, Noullez, Alain, Bruno, Roberto, Bavassano, Bruno, and Pietropaolo, Ermanno
- Subjects
Astrophysics ,Nonlinear Sciences - Chaotic Dynamics ,Physics - Plasma Physics - Abstract
We show in this article direct evidence for the presence of an inertial energy cascade, the most characteristic signature of hydromagnetic turbulence (MHD), in the solar wind as observed by the Ulysses spacecraft. After a brief rederivation of the equivalent of Yaglom's law for MHD turbulence, we show that a linear relation is indeed observed for the scaling of mixed third order structure functions involving Els\"asser variables. This experimental result, confirming the prescription stemming from a theorem for MHD turbulence, firmly establishes the turbulent character of low-frequency velocity and magnetic field fluctuations in the solar wind plasma.
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- 2007
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6. On the intermittent character of interplanetary magnetic field fluctuations
- Author
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Bruno, Roberto, Carbone, Vincenzo, Chapman, Sandra, Hnat, Bogdan, Noullez, Alain, and Sorriso-Valvo, Luca
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Astrophysics ,Physics - Fluid Dynamics ,Physics - Space Physics - Abstract
Interplanetary magnetic field magnitude fluctuations are notoriously more intermittent than velocity fluctuations in both fast and slow wind. This behaviour has been interpreted in terms of the anomalous scaling observed in passive scalars in fully developed hydrodynamic turbulence. In this paper, the strong intermittent nature of the interplanetary magnetic field is briefly discussed comparing results performed during different phases of the solar cycle. The scaling properties of the interplanetary magnetic field magnitude show solar cycle variation that can be distinguished in the scaling exponents revealed by structure functions. The scaling exponents observed around solar maximum coincide, within the errors, to those measured for passive scalars in hydrodynamic turbulence. However, it is also found that the values are not universal in the sense that the solar cycle variation may be reflected in dependence on the structure of the velocity field., Comment: 19 pages, in press on Physics of Plasmas
- Published
- 2007
- Full Text
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7. The global picture of self-similar and not self-similar decay in Burgers Turbulence
- Author
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Noullez, Alain, Gurbatov, Sergey N., Aurell, Erik, and Simdyankin, Sergey I.
- Subjects
Nonlinear Sciences - Chaotic Dynamics - Abstract
This paper continue earlier investigations on the decay of Burgers turbulence in one dimension from Gaussian random initial conditions of the power-law spectral type $E_0(k)\sim|k|^n$. Depending on the power $n$, different characteristic regions are distinguished. The main focus of this paper is to delineate the regions in wave-number $k$ and time $t$ in which self-similarity can (and cannot) be observed, taking into account small-$k$ and large-$k$ cutoffs. The evolution of the spectrum can be inferred using physical arguments describing the competition between the initial spectrum and the new frequencies generated by the dynamics. For large wavenumbers, we always have $k^{-2}$ region, associated to the shocks. When $n$ is less than one, the large-scale part of the spectrum is preserved in time and the global evolution is self-similar, so that scaling arguments perfectly predict the behavior in time of the energy and of the integral scale. If $n$ is larger than two, the spectrum tends for long times to a universal scaling form independent of the initial conditions, with universal behavior $k^2$ at small wavenumbers. In the interval $2
- Published
- 2004
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8. Going forth and back in time: a fast and parsimonious algorithm for mixed initial/final-value problems
- Author
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Celani, Antonio, Cencini, Massimo, and Noullez, Alain
- Subjects
Physics - Computational Physics ,Nonlinear Sciences - Chaotic Dynamics ,Physics - Fluid Dynamics - Abstract
We present an efficient and parsimonious algorithm to solve mixed initial/final-value problems. The algorithm optimally limits the memory storage and the computational time requirements: with respect to a simple forward integration, the cost factor is only logarithmic in the number of time-steps. As an example, we discuss the solution of the final-value problem for a Fokker-Planck equation whose drift velocity solves a different initial-value problem -- a relevant issue in the context of turbulent scalar transport., Comment: 12 pages, 4 figures
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- 2003
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9. Topological changes of the photospheric magnetic field inside active regions: a prelude to flares
- Author
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Sorriso-Valvo, L., Carbone, V., Abramenko, V., Yurchyshyn, V., Noullez, A., Politano, H., Pouquet, A., and Veltri, P.
- Subjects
Astrophysics ,Nonlinear Sciences - Chaotic Dynamics ,Physics - Space Physics - Abstract
The observations of magnetic field variations as a signature of flaring activity is one of the main goal in solar physics. Some efforts in the past give apparently no unambiguous observations of changes. We observed that the scaling laws of the current helicity inside a given flaring active region change clearly and abruptly in correspondence with the eruption of big flares at the top of that active region. Comparison with numerical simulations of MHD equations, indicates that the change of scaling behavior in the current helicity, seems to be associated to a topological reorganization of the footpoint of the magnetic field loop, namely to dissipation of small scales structures in turbulence. It is evident that the possibility of forecasting in real time high energy flares, even if partially, has a wide practical interest to prevent the effects of big flares on Earth and its environment., Comment: 23 pages, submitted to Planetary and Space Science (Jul 2002)
- Published
- 2002
10. Analysis of cancellation in two-dimensional magnetohydrodynamic turbulence
- Author
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Sorriso-Valvo, L., Carbone, V., Noullez, A., Politano, H., Pouquet, A., and Veltri, P.
- Subjects
Nonlinear Sciences - Chaotic Dynamics ,Physics - Data Analysis, Statistics and Probability ,Physics - Fluid Dynamics ,Physics - Plasma Physics - Abstract
A signed measure analysis of two-dimensional intermittent magnetohydrodynamic turbulence is presented. This kind of analysis is performed to characterize the scaling behavior of the sign-oscillating flow structures, and their geometrical properties. In particular, it is observed that cancellations between positive and negative contributions of the field inside structures, are inhibited for scales smaller than the Taylor microscale, and stop near the dissipative scale. Moreover, from a simple geometrical argument, the relationship between the cancellation exponent and the typical fractal dimension of the structures in the flow is obtained., Comment: 21 pages, 5 figures (3 .jpg not included in the latex file)
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- 2001
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11. Heap-based algorithm for one-dimensional particle systems
- Author
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Noullez, Alain, Fanelli, Duccio, and Aurell, Erik
- Subjects
Condensed Matter - Disordered Systems and Neural Networks ,Astrophysics ,Nonlinear Sciences - Chaotic Dynamics - Abstract
A fast algorithm to study one-dimensional self-gravitating systems, and, more generally, systems that are Lagrangian integrable between collisions, is presented. The algorithm is event-driven, and uses a heap-ordered set of predicted future events. In the limit of large number of particles $N$, the operation count is dominated by the cost of reordering the heap after each event, which goes asymptotically as $\log N$. Some applications are discussed in detail., Comment: submitted to J. Comput. Phys
- Published
- 2001
12. Lagrangian method for multiple correlations in passive scalar advection
- Author
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Frisch, U., Mazzino, A., Noullez, A., and Vergassola, M.
- Subjects
Condensed Matter - Statistical Mechanics ,Condensed Matter - Disordered Systems and Neural Networks - Abstract
A Lagrangian method is introduced for calculating simultaneous n-point correlations of a passive scalar advected by a random velocity field, with random forcing and finite molecular diffusivity kappa. The method, which is here presented in detail, is particularly well suited for studying the kappa tending to 0 limit when the velocity field is not smooth. Efficient Monte Carlo simulations based on this method are applied to the Kraichnan model of passive scalar and lead to accurate determinations of the anomalous intermittency corrections in the fourth-order structure function as a function of the scaling exponent xi of the velocity field in two and three dimensions. Anomalous corrections are found to vanish in the limits xi tending to 0 and xi tending to 2, as predicted by perturbation theory., Comment: 11 pages, LATEX, 8 figures. To appear in Phys. Fluids (revised version, minor corrections) Special issue Proceedings of the May 1998 Los Alamos workshop in honor of Robert H. Kraichnan
- Published
- 1998
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13. Bifractality of the Devil's staircase appearing in the Burgers equation with Brownian initial velocity
- Author
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Aurell, E., Frisch, U., Noullez, A., and Blank, M.
- Subjects
Nonlinear Sciences - Chaotic Dynamics - Abstract
It is shown that the inverse Lagrangian map for the solution of the Burgers equation (in the inviscid limit) with Brownian initial velocity presents a bifractality (phase transition) similar to that of the Devil's staircase for the standard triadic Cantor set. Both heuristic and rigorous derivations are given. It is explained why artifacts can easily mask this phenomenon in numerical simulations., Comment: 12 pages, LaTeX
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- 1996
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14. Satellite orbits design using frequency analysis
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Noullez, A., Tsiganis, K., and Tzirti, S.
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- 2015
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15. Design of low-altitude Martian orbits using frequency analysis
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Alain Noullez, Kleomenis Tsiganis, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Centre National de la Recherche Scientifique (CNRS), Department of Physics [Thessaloniki], and Aristotle University of Thessaloniki
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,media_common.quotation_subject ,Aerospace Engineering ,01 natural sciences ,law.invention ,Satellite Orbits ,Gravitational field ,Mars Orbits ,law ,0103 physical sciences ,Eccentricity (behavior) ,Variation (astronomy) ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,media_common ,Physics ,Martian ,Orbital elements ,Frequency analysis ,Frozen Orbits ,[PHYS.PHYS]Physics [physics]/Physics [physics] ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,Frequency Analysis ,Astronomy and Astrophysics ,Geodesy ,[SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM] ,Geophysics ,Amplitude ,Space and Planetary Science ,Physics::Space Physics ,Orbit (dynamics) ,General Earth and Planetary Sciences ,Astrophysics::Earth and Planetary Astrophysics - Abstract
Nearly-circular Frozen Orbits (FOs) around axisymmetric bodies – or, quasi-circular Periodic Orbits (POs) around non-axisymmetric bodies – are of primary concern in the design of low-altitude survey missions. Here, we study very low-altitude orbits (down to 50 km) in a high-degree and order model of the Martian gravity field. We apply Prony’s Frequency Analysis (FA) to characterize the time variation of their orbital elements by computing accurate quasi-periodic decompositions of the eccentricity and inclination vectors. An efficient, iterative filtering algorithm, previously applied to lunar orbiters, complements the method and is used to accurately compute the locations of POs/FOs, for a wide range of initial conditions. By defining the ’distance’ of any orbit from the family of POs and using the relative amplitudes of the different components of the motion, we can build ’dynamical fate maps’ that graphically depict the survivability of low-eccentricity, low-altitude orbits at every inclination, and can be used for efficient mission planning. While lowering the altitude generally enhances the effect of tesseral and sectorial gravity harmonics, we find this to have less consequence for low altitude Martian satellites, in contrast with the Lunar case. Hence, a high-degree ( ≃ 20 th ) axisymmetric model is adequate for preliminary mission design at moderate altitudes, but should be complemented at low altitudes by the methods described here. All families of POs and their spectral decompositions can be accurately and effectively computed by continuation in arbitrarily complex Martian gravity models, as our filtering algorithm requires only short integration arcs.
- Published
- 2021
16. Lagrangian Method for Multiple Correlations in Passive Scalar Advection
- Author
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Frisch, U., Mazzino, A., Noullez, A., Vergassola, M., Moreau, R., editor, Kambe, Tsutomu, editor, Nakano, Tohru, editor, and Miyauchi, Toshio, editor
- Published
- 2001
- Full Text
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17. Transverse Structure in Turbulent Flow Using the Relief Technique
- Author
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Noullez, A., Frisch, U., Wallace, G., Lempert, W., Miles, R. B., Moreau, R., editor, and Frisch, Uriel, editor
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- 1998
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18. The magnetohydrodynamic turbulent cascade in the ecliptic solar wind: Study of Ulysses data
- Author
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Marino, Raffaele, Sorriso-Valvo, Luca, Carbone, Vincenzo, Veltri, Pierluigi, Noullez, Alain, and Bruno, Roberto
- Published
- 2011
- Full Text
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19. Secular dynamics of a lunar orbiter: a global exploration using Prony’s frequency analysis
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Tzirti, S., Noullez, A., and Tsiganis, K.
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- 2014
- Full Text
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20. The Energy Cascade in Solar Wind MHD Turbulence
- Author
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Marino, R., Sorriso-Valvo, L., Carbone, V., Noullez, A., Bruno, R., and Bavassano, B.
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- 2009
- Full Text
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21. Turbulence Homogeneity and Isotropy : Mean-field and Fluctuations in the Taylor-Green vortex
- Author
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Noullez, A., Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
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Physics::Fluid Dynamics ,Turbulence simulation < Turbulent Flows ,Isotropic turbulence < Turbulent Flows ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,Homogeneous turbulence < Turbulent Flows ,[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] ,[SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] - Abstract
We have performed medium resolution numerical simulations over very long times of the stationary turbulent flow that develops from a static constant in time Taylor-Green forcing. By averaging over thousands of large-scale eddy turnover times, we separate the turbulent fluctuations from the inhomogeneous anisotropic mean flow induced by the forcing. We show that the turbulent velocity fluctuations are only slightly more isotropic than the total flow and still display significant deviations from isotropy and homogeneity. Also, the fluctuations and the mean flow are not independent, and their energies are locally anticorrelated. The energy transfer laws of Kolmogorov, Yaglom and Monin and their corresponding finite Reynolds number corrections are also checked for different positions and orientations in the flow, and it is found that Kolmogorov and Yaglom laws are not completely satisfied due to the imperfect return to isotropy and homogeneity of the flow. Monin's relation is verified because it averages dissipation over the different directions and in a volume such that homogeneity is restored, and also only for the total fluid velocity and not for the velocity fluctuations as these do not obey Navier-Stokes equations. These results suggest that the hypothesis of small scale homogeneous and isotropic turbulence should be clarified in the presence of an inhomogeneous anisotropic mean flow induced by forcing. We have performed medium resolution numerical simulations over very long times of the stationary turbulent flow that develops from a static constant in time Taylor-Green forcing. By averaging over thousands of large-scale eddy turnover times, we separate the turbulent fluctuations from the inhomogeneous anisotropic mean flow induced by the forcing. We show that the turbulent velocity fluctuations are only slightly more isotropic than the total flow and still display significant deviations from isotropy and homogeneity. Also, the fluctuations and the mean flow are not independent, and their energies are locally anticorrelated. The energy transfer laws of Kolmogorov, Yaglom and Monin and their corresponding finite Reynolds number corrections are also checked for different positions and orientations in the flow, and it is found that Kolmogorov and Yaglom laws are not completely satisfied due to the imperfect return to isotropy and homogeneity of the flow. Monin's relation is verified because it averages dissipation over the different directions and in a volume such that homogeneity is restored, and also only for the total fluid velocity and not for the velocity fluctuations as these do not obey Navier-Stokes equations. These results suggest that the hypothesis of small scale homogeneous and isotropic turbulence should be clarified in the presence of an inhomogeneous anisotropic mean flow induced by forcing.
- Published
- 2020
22. A Frequency Selective Filter for Short-Length Time Series
- Author
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Iacobucci, Alessandra and Noullez, Alain
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- 2005
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23. Global fluctuations in decaying Burgers turbulence
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Noullez, A. and Pinton, J.-F.
- Published
- 2002
- Full Text
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24. Bifractality of the devil’s staircase appearing in the burgers equation with brownian initial velocity
- Author
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Aurell, E., Frisch, U., Noullez, A., and Blank, M.
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- 1997
- Full Text
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25. A fast Legendre transform algorithm and applications to the adhesion model
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Noullez, A. and Vergassola, M.
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- 1994
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26. Lagrangian Method for Multiple Correlations in Passive Scalar Advection
- Author
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Frisch, U., primary, Mazzino, A., additional, Noullez, A., additional, and Vergassola, M., additional
- Published
- 2001
- Full Text
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27. Going forth and back in time: a fast and parsimonious algorithm for mixed initial/final-value problems
- Author
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Celani, Antonio, Cencini, Massimo, and Noullez, Alain
- Published
- 2004
- Full Text
- View/download PDF
28. Topological changes of the photospheric magnetic field inside active regions: A prelude to flares?
- Author
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Sorriso-Valvo, Luca, Carbone, Vincenzo, Veltri, Pierluigi, Abramenko, Valentina I., Noullez, Alain, Politano, Hélène, Pouquet, Annick, and Yurchyshyn, Vasyl
- Published
- 2004
- Full Text
- View/download PDF
29. Satellite orbits design using frequency analysis
- Author
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Kleomenis Tsiganis, S. Tzirti, Alain Noullez, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Thessaloniki], and Aristotle University of Thessaloniki
- Subjects
Physics ,Orbital elements ,Atmospheric Science ,[PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM] ,Computation ,Mathematical analysis ,Aerospace Engineering ,Astronomy and Astrophysics ,Orbital eccentricity ,Frozen orbit ,Measure (mathematics) ,Geophysics ,Classical mechanics ,Space and Planetary Science ,Physics::Space Physics ,Orbit (dynamics) ,General Earth and Planetary Sciences ,Satellite ,Astrophysics::Earth and Planetary Astrophysics ,ComputingMilieux_MISCELLANEOUS ,Halo orbit - Abstract
We present here a new method for the efficient computation of periodic orbits, which are of particular interest for low-altitude satellite orbits design in high degree/order, non-axisymmetric gravity models. Our method consists of an iterative filtering scheme, that is itself based on ‘Prony’s method’ of frequency analysis, and is independent of the complexity of the gravity model. Applying this method to the case of a low-altitude lunar orbiter, we show that it converges rapidly, in all models and for all values of altitude and initial inclination studied. Thus, as demonstrated below, one could use it to correct the initial conditions of a desired mission orbit — usually defined within the framework of a simplified model (e.g. the ‘ J 2 problem’) — ensuring minimal orbital eccentricity variations and, for very low altitudes, collision avoidance. At the same time, an accurate quasi-periodic decomposition of the orbit is computed, giving a measure of the periodic fluctuations of the orbital parameters.
- Published
- 2015
30. Development, Growth, and Form in Living Systems
- Author
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Boon, Jean-Pierre, Noullez, Alain, Stanley, H. Eugene, editor, and Ostrowsky, Nicole, editor
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- 1986
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31. Negative Magnetic Eddy Diffusivities from Test-Field Method and Multiscale Stability Theory
- Author
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Vladislav Zheligovsky, Axel Brandenburg, Alain Noullez, Alexander Andrievsky, Nordic Institute of Theoretical Physics, Nordic Institute for Theoretical Physics (NORDITA), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[PHYS.PHYS.PHYS-FLU-DYN]Physics [physics]/Physics [physics]/Fluid Dynamics [physics.flu-dyn] ,FOS: Physical sciences ,Symmetry group ,01 natural sciences ,Homogenization (chemistry) ,010305 fluids & plasmas ,Eddy diffusion ,Physics::Fluid Dynamics ,Stability theory ,0103 physical sciences ,Tensor ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,ComputingMilieux_MISCELLANEOUS ,Physics ,Turbulence ,Mathematical analysis ,Fluid Dynamics (physics.flu-dyn) ,Astronomy and Astrophysics ,Physics - Fluid Dynamics ,Nonlinear Sciences - Chaotic Dynamics ,Magnetic field ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Chaotic Dynamics (nlin.CD) ,Self-adjoint operator - Abstract
The generation of large-scale magnetic field in the kinematic regime in the absence of an alpha-effect is investigated by following two different approaches, namely the test-field method and multiscale stability theory relying on the homogenisation technique. We show analytically that the former, applied for the evaluation of magnetic eddy diffusivities, yields results that fully agree with the latter. Our computations of the magnetic eddy diffusivity tensor for the specific instances of the parity-invariant flow-IV of G.O. Roberts and the modified Taylor-Green flow in a suitable range of parameter values confirm the findings of previous studies, and also explain some of their apparent contradictions. The two flows have large symmetry groups; this is used to considerably simplify the eddy diffusivity tensor. Finally, a new analytic result is presented: upon expressing the eddy diffusivity tensor in terms of solutions to auxiliary problems for the adjoint operator, we derive relations between magnetic eddy diffusivity tensors that arise for opposite small-scale flows v(x) and -v(x)., Comment: 29 pp., 19 figures, 42 references
- Published
- 2015
32. Lattice Gas Simulation of 2-D Viscous Fingering
- Author
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Bonetti, M., Noullez, A., Boon, J.-P., Lotsch, H. K. V., editor, Manneville, Paul, editor, Boccara, Nino, editor, Vichniac, Gérard Y., editor, and Bidaux, Roger, editor
- Published
- 1989
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33. Secular dynamics of a lunar orbiter: a global exploration using Prony’s frequency analysis
- Author
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S. Tzirti, Kleomenis Tsiganis, Alain Noullez, Department of Physics [Thessaloniki], Aristotle University of Thessaloniki, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Physics ,Orbital elements ,[PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM] ,Degree (graph theory) ,Applied Mathematics ,media_common.quotation_subject ,Mathematical analysis ,Spherical harmonics ,Astronomy and Astrophysics ,Omega ,Computational Mathematics ,Classical mechanics ,Amplitude ,13. Climate action ,Space and Planetary Science ,Modeling and Simulation ,Harmonic ,Orbit (dynamics) ,Astrophysics::Earth and Planetary Astrophysics ,Eccentricity (behavior) ,Mathematical Physics ,ComputingMilieux_MISCELLANEOUS ,media_common - Abstract
We study the secular dynamics of lunar orbiters, in the framework of high-degree gravity models. To achieve a global view of the dynamics, we apply a frequency analysis (FA) technique which is based on Prony’s method. This allows for an extensive exploration of the eccentricity ( $$e$$ )—inclination ( $$i$$ ) space, based on short-term integrations ( $$\sim $$ 8 months) over relatively high-resolution grids of initial conditions. Different gravity models are considered: 3rd, 7th and 10th degree in the spherical harmonics expansion, with the main perturbations from the Earth being added. Since the dynamics is mostly regular, each orbit is characterised by a few parameters, whose values are given by the spectral decomposition of the orbital elements time series. The resulting frequency and amplitude maps in ( $$e_0,i_0$$ ) are used to identify the dominant perturbations and deduce the “minimum complexity” model necessary to capture the essential features of the long-term dynamics. We find that the 7th degree zonal harmonic ( $$J_7$$ term) is of profound importance at low altitudes as, depending on the initial secular phases, it can lead to collision with the Moon’s surface within a few months. The 3rd-degree non-axisymmetric terms are enough to describe the deviations from the 1 degree-of-freedom zonal problem; their main effect is to modify the equilibrium value of the argument of periselenium, $$\omega $$ , with respect to the “frozen” solution ( $$\omega =\pm 90^{\circ }, \forall \Omega $$ , where $$\Omega $$ is the nodal longitude). Finally, we show that using FA on a fine grid of initial conditions, set around a suitably chosen ‘first guess’, one can compute an accurate approximation of the initial conditions of a periodic orbit.
- Published
- 2014
34. TRANSVERSE STRUCTURE IN TURBULENT FLOW USING THE RELIEF TECHNIQUE (Statistical Nature of Turbulence and its Dynamical Description based on coherent structures)
- Author
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Noullez, A., Wallace, G., Lempert, W., Miles, R.B., and Frisch, U.
- Published
- 2000
35. Negative magnetic eddy diffusivities from the test-field method and multiscale stability theory
- Author
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Andrievsky, Alexander, Brandenburg, Axel, Noullez, Alain, Zheligovsky, Vladislav, Andrievsky, Alexander, Brandenburg, Axel, Noullez, Alain, and Zheligovsky, Vladislav
- Abstract
The generation of a large-scale magnetic field in the kinematic regime in the absence of an alpha-effect is investigated by following two different approaches: the test-field method and the multiscale stability theory relying on the homogenization technique. Our computations of the magnetic eddy diffusivity tensor of the parity-invariant flow IV of G. O. Roberts and the modified Taylor-Green flow confirm the findings of previous studies. and also explain some of their apparent contradictions. The two flows have large symmetry groups; this is used to considerably simplify the eddy diffusivity tensor. Finally, a new analytic result is presented: upon expressing the eddy diffusivity tensor in terms of solutions to auxiliary problems for the adjoint operator, we derive relations between the magnetic eddy diffusivity tensors that arise for mutually reverse small-scale flows v(x) and - v(x)., QC 20151124
- Published
- 2015
- Full Text
- View/download PDF
36. Un éloge et l’heure où il vient
- Author
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Lucien Noullez
- Abstract
Guy GOFFETTE, Eloge pour une cuisine de province, poèmes, postface de Jacques Borel, Seyssel, Champ Vallon, 1988, 171 p. La Parole a, dit-on, planté sa tente parmi nous. La Nomadie de Guy Goffette s’y est abritée et, depuis, le poète n’a de cesse. Editeur-typographe, animateur de la splendide revue Triangle, Goffette vient de recevoir le Prix Triennal de Littérature. On s’étonne d’en entendre parler si peu. En matière de poésie, le silence des critiques correspond, il est vrai, à l’hermétism...
- Published
- 2013
37. A fast Legendre transform algorithm and applications to the adhesion model
- Author
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Alain Noullez, Massimo Vergassola, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Binary search algorithm ,Computation ,[INFO.INFO-DS]Computer Science [cs]/Data Structures and Algorithms [cs.DS] ,01 natural sciences ,Cosmology ,010305 fluids & plasmas ,Theoretical Computer Science ,Legendre transformation ,symbols.namesake ,0103 physical sciences ,[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] ,010306 general physics ,ComputingMilieux_MISCELLANEOUS ,Mathematics ,Numerical Analysis ,Conservation law ,Applied Mathematics ,Mathematical analysis ,General Engineering ,Grid ,Burgers' equation ,Mathematical theory ,Computational Mathematics ,Computational Theory and Mathematics ,symbols ,Algorithm ,[MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA] ,Software - Abstract
A new algorithm for the computation of discrete Legendre transforms is discussed. Classical solutions have a running time proportional toN 2d , whereN is the size of the spatial grid andd is the space dimension. The new algorithm has a running timeO((N log2 N) d ). A general application of this algorithm is to the weak solutions of hyperbolic systems of conservation laws as considered by Lax (1973,Hyperbolic Systems of Conservation Laws and the Mathematical Theory of Shock Waves, S.I.A.M.). The potential of the method is illustrated on the “adhesion model,” a multi-dimensional version of the Burgers equation, used to study the formation of large-scale structures in cosmology.
- Published
- 1994
38. NEGATIVE MAGNETIC EDDY DIFFUSIVITIES FROM THE TEST-FIELD METHOD AND MULTISCALE STABILITY THEORY
- Author
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Andrievsky, Alexander, primary, Brandenburg, Axel, additional, Noullez, Alain, additional, and Zheligovsky, Vladislav, additional
- Published
- 2015
- Full Text
- View/download PDF
39. Sorriso-Valvoet al.Reply
- Author
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Roberto Bruno, Vincenzo Carbone, L. Sorriso Valvo, Raffaele Marino, Alain Noullez, and Pierluigi Veltri
- Subjects
Physics ,0103 physical sciences ,General Physics and Astronomy ,010306 general physics ,010303 astronomy & astrophysics ,01 natural sciences - Published
- 2010
40. Compressive turbulent cascade and heating in the solar wind
- Author
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R. Marino, L. Sorriso-Valvo, V. Carbone, A. Noullez, R. Bruno, M. Maksimovic, K. Issautier, N. Meyer-Vernet, M. Moncuquet, and F. Pantellini
- Subjects
Physics ,Solar wind ,Amplitude ,Cascade ,Turbulence ,Energy cascade ,Physics::Space Physics ,Astrophysics::Solar and Stellar Astrophysics ,Mechanics ,Plasma ,Astrophysics ,Magnetohydrodynamics ,Scaling - Abstract
A turbulent energy cascade has been recently identified in high‐latitude solar wind data samples by using a Yaglom‐like relation. However, analogous scaling law, suitably modified to take into account compressible fluctuations, has been observed in a much more extended fraction of the same data set recorded by the Ulysses spacecraft. Thus, it seems that large scale density fluctuations, despite their low amplitude, play a major role in the basic scaling properties of turbulence. The compressive turbulent cascade, moreover, seems to be able to supply the energy needed to account for the local heating of the non‐adiabatic solar wind.
- Published
- 2010
41. Comment on 'Scaling Laws of Turbulence and Heating of Fast Solar Wind: The Role of Density Fluctuations' Sorriso-Valvo et al. Reply
- Author
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Sorriso-Valvo L, Carbone V, Marino R, Noullez A, Bruno R, and Veltri P
- Published
- 2010
42. Scaling Laws of Turbulence and Heating of Fast SolarWind: The Role of Density Fluctuations
- Author
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Vincenzo Carbone, Raffaele Marino, Luca Sorriso-Valvo, Alain Noullez, Roberto Bruno, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
K-epsilon turbulence model ,General Physics and Astronomy ,Energy flux ,FOS: Physical sciences ,K-omega turbulence model ,Magnetohydrodynamic turbulence ,01 natural sciences ,Physics::Fluid Dynamics ,Physics - Space Physics ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,010306 general physics ,010303 astronomy & astrophysics ,Scaling ,Physics ,Turbulence ,Fluid Dynamics (physics.flu-dyn) ,Physics - Fluid Dynamics ,Mechanics ,Dissipation ,Physics - Plasma Physics ,Space Physics (physics.space-ph) ,Plasma Physics (physics.plasm-ph) ,Solar wind ,Classical mechanics ,Physics::Space Physics - Abstract
Incompressible and isotropic magnetohydrodynamic turbulence in plasmas can be described by an exact relation for the energy flux through the scales. This Yaglom-like scaling law has been recently observed in the solar wind above the solar poles observed by the Ulysses spacecraft, where the turbulence is in an Alfveacutenic state. An analogous phenomenological scaling law, suitably modified to take into account compressible fluctuations, is observed more frequently in the same data set. Large-scale density fluctuations, despite their low amplitude, thus play a crucial role in the basic scaling properties of turbulence. The turbulent cascade rate in the compressive case can, moreover, supply the energy dissipation needed to account for the local heating of the nonadiabatic solar wind.
- Published
- 2010
- Full Text
- View/download PDF
43. Scaling laws in solar wind turbulence
- Author
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Marino,Raffaele, Falcone, Giovanni, Carbone, Vincenzo, Noullez, Alain, and Sorriso Salvo, Luca
- Subjects
Astrofisica ,Vento solare ,Turbolenza - Abstract
Dottorato di Ricerca in Fisica, Ciclo XXII, 2009 Università della Calabria
- Published
- 2009
44. Turbulence and intermittency in the heliospheric magnetic field in fast and slow solar wind
- Author
-
Alain Noullez, R. von Steiger, Emiliya Yordanova, and André Balogh
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Astrophysics::High Energy Astrophysical Phenomena ,Soil Science ,STREAMS ,Aquatic Science ,Oceanography ,7. Clean energy ,01 natural sciences ,law.invention ,Geochemistry and Petrology ,law ,Intermittency ,0103 physical sciences ,Earth and Planetary Sciences (miscellaneous) ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Physics::Atmospheric and Oceanic Physics ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Water Science and Technology ,Physics ,Ecology ,Turbulence ,Paleontology ,Forestry ,Geophysics ,Solar physics ,Magnetic field ,Solar wind ,13. Climate action ,Space and Planetary Science ,Physics::Space Physics ,Polar ,Astrophysics::Earth and Planetary Astrophysics ,Heliosphere - Abstract
[1] We study the nonuniform solar wind turbulence using high-resolution Ulysses magnetic field data measured at different solar activity level, heliospheric latitudes, and distance. We define several types of solar wind dependent of the coronal region of origin and also of the dynamical behavior of the different streams, namely, “pure” fast wind, fast streams, “pure” slow wind, and slow streams. The turbulent properties of the solar wind types were investigated in terms of their scaling properties and spatial inhomogeneity. A clear trend in the power spectrum of the solar wind magnetic field magnitude is observed: the “pure” fast wind has a slope ∼−1.33 (1/f-like), the fast streams ∼−1.48 (Kraichnan-like), the “pure” slow wind ∼−1.67 (Kolmogorov-like), and the slow streams ∼−1.72. We find that the “pure” fast wind in the polar heliolatitudes is less intermittent than the other types: “pure” slow wind and both slow and fast streams, which is because of the absence of dynamical interactions between streams with different speeds. On the other hand, fast streams are more intermittent than the “pure” fast wind, and slow streams are less intermittent than the “pure” slow winds. A clear radial and latitudinal evolution of the intermittency is observed only for the “pure” fast wind, while in the equatorial plane, the fast streams, the “pure” slow wind, and the slow streams do not show evolution either in heliolatitude or in heliocentric distance.
- Published
- 2009
45. Turbulence and intermittency in the heliospheric magnetic field in fast and slow solar wind
- Author
-
Yordanova, E., Balogh, A., Noullez, A., Von Steiger, R., Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[SDU]Sciences of the Universe [physics] - Abstract
Journal of Geophysical Research (Space Physics), 114, p. 08101 (2009); International audience
- Published
- 2009
46. Long-time correlations in a 2D lattice gas
- Author
-
Alain Noullez, Jean-Pierre Boon, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[PHYS.PHYS.PHYS-FLU-DYN]Physics [physics]/Physics [physics]/Fluid Dynamics [physics.flu-dyn] ,Physique de l'état condense [struct. électronique, etc.] ,Tagged particle ,Autocorrelation ,Spectral density ,Statistical and Nonlinear Physics ,Geometry ,Physique de l'état condense [struct. propr. thermiques, etc.] ,Physique des phénomènes non linéaires ,Condensed Matter Physics ,01 natural sciences ,Power law ,Cellular automaton ,010305 fluids & plasmas ,Computational physics ,Time correlation ,Physique statistique classique et relativiste ,Colored ,Lattice (order) ,0103 physical sciences ,[NLIN.NLIN-CG]Nonlinear Sciences [physics]/Cellular Automata and Lattice Gases [nlin.CG] ,010306 general physics ,Physique de l'état condense [supraconducteur] ,ComputingMilieux_MISCELLANEOUS ,Mathematics - Abstract
We present the results of CA simulations of a moderately dense lattice gas using an extended version of the FHP model for colored automata. By tracking a tagged particle, we construct its velocity autocorrelation function and we show that the corresponding power spectrum exhibits a low-frequency contribution characteristic of the long-time power law behavior (≈ t-1, in 2D). © 1991., SCOPUS: ar.j, info:eu-repo/semantics/published
- Published
- 1991
47. Evolution of anisotropic structures and turbulence in the multidimensional Burgers equation
- Author
-
Alexander Yu. Moshkov, Alain Noullez, Sergey N. Gurbatov, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Physics ,Field (physics) ,Turbulence ,Reynolds number ,Dissipation ,01 natural sciences ,010305 fluids & plasmas ,Burgers' equation ,symbols.namesake ,Nonlinear system ,Nonlinear acoustics ,0103 physical sciences ,symbols ,Statistical physics ,010306 general physics ,Anisotropy - Abstract
The goal of the present paper is the investigation of the final evolution of anisotropic regular structures and turbulence at large Reynolds number in the multidimensional Burgers equation. We show that we have local isotropization at small scales of the velocity and potential fields inside cellular zones. For periodic waves, we have simple decay inside a frozen structure. The global structure at large times is determined by the initial correlations and for short range correlated fields we have isotropization of turbulence. Finally, we consider the final behavior of the field, when the processes of nonlinear beating interactions become frozen, and the evolution of the field is determined only by the linear dissipation.
- Published
- 2008
48. Recent insights in solar wind MHD turbulence
- Author
-
R. Bruno, V. Carbone, R. Marino, L. Sorriso-Valvo, A. Noullez, R. D’Amicis, B. Bavassano, E. Pietropaolo, Gang Li, Qiang Hu, Olga Verkhoglyadova, Gary P. Zank, R. P. Lin, and J. Luhmann
- Subjects
Shock wave ,Physics ,Solar wind ,Wind profile power law ,Solar flare ,Turbulence ,Energy cascade ,Physics::Space Physics ,Astrophysics::Solar and Stellar Astrophysics ,Mechanics ,Astrophysics ,Magnetohydrodynamics ,Scaling - Abstract
In this short review we report about recent findings related to two fundamental points in the study of solar wind turbulence: a) the verification of the equivalent of the −4/5 law in the solar wind and b) the estimate of the energy cascade along the spectrum and its comparison with the heating rate necessary to heat the solar wind during its expansion as deduced from in‐situ measurements. As a matter of fact, a Yaglom‐like scaling relation has recently been found in both high‐latitude and in‐ecliptic data samples. However, analogous scaling law, suitably modified to take into account compressible fluctuations, has been observed in a much more extended fraction of the same data set recorded at high latitude. Thus, it seems that large scale density fluctuations, despite their low amplitude, play a major role in the basic scaling properties of turbulence. The compressive turbulent cascade, moreover, seems to be able to supply the energy needed to account for the local heating of the non‐adiabatic solar wind.
- Published
- 2008
49. A model for two-dimensional bursty turbulence in magnetized plasmas
- Author
-
Alain Noullez, Kristoffer Rypdal, Vincenzo Carbone, Leonardo Primavera, Sergio Servidio, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Electromagnetic field ,Physics ,Drift velocity ,Turbulence ,Mechanics ,Vorticity ,Condensed Matter Physics ,Curvature ,01 natural sciences ,Instability ,010305 fluids & plasmas ,Magnetic field ,0103 physical sciences ,Statistical physics ,Magnetohydrodynamics ,010306 general physics - Abstract
The nonlinear dynamics of two-dimensional electrostatic interchange modes in a magnetized plasma is investigated through a simple model that replaces the instability mechanism due to magnetic field curvature by an external source of vorticity and mass. Simulations in a cylindrical domain, with a spatially localized and randomized source at the center of the domain, reveal the eruption of mushroom-shaped bursts that propagate radially and are absorbed by the boundaries. Burst sizes and the interburst waiting times exhibit power-law statistics, which indicates long-range interburst correlations, similar to what has been found in sandpile models for avalanching systems. It is shown from the simulations that the dynamics can be characterized by a Yaglom relation for the third-order mixed moment involving the particle number density as a passive scalar and the E×B drift velocity, and hence that the burst phenomenology can be described within the framework of turbulence theory. Statistical features are qualitat...
- Published
- 2008
50. Heating the Solar Wind by a Magnetohydrodynamic Turbulent Energy Cascade
- Author
-
Raffaele Marino, Vincenzo Carbone, B. Bavassano, Roberto Bruno, Luca Sorriso-Valvo, Alain Noullez, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010504 meteorology & atmospheric sciences ,ULYSSES ,Stellar-wind bubble ,Atmospheric sciences ,7. Clean energy ,01 natural sciences ,0103 physical sciences ,Coronal mass ejection ,Astrophysics::Solar and Stellar Astrophysics ,Interplanetary magnetic field ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,SOLAR WIND ,Physics ,PLASMA ,Astronomy and Astrophysics ,Mechanics ,EVOLUTION ,Solar wind ,Polar wind ,13. Climate action ,Space and Planetary Science ,Energy cascade ,Physics::Space Physics ,TURBULENCE ,Magnetopause ,Magnetohydrodynamics - Abstract
Solar wind plasma is known to cool down more slowly while it is blown away from the Sun than expected from an adiabatic spherical expansion. Some source of heating is thus needed to explain the observed temperature radial profile. The presence of a nonlinear turbulent magnetohydrodynamic energy cascade has been recently observed in solar wind plasma. This provides for the first time a direct estimation of the turbulent energy transfer rate, which can contribute to the in situ heating of the wind. The value of such contribution is shown to represent an important fraction ( from 5% to 100%) of the total heating, and is strongly correlated with the wind temperature.
- Published
- 2008
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