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In previous works, we derived stationary density distribution functions (DDF) where the local equilibrium is determined by imposing the maximum entropy (MaxEnt) principle, under the scale invariance restrictions, and the minimum entropy production theorem. In this paper we demonstrate that it is possible to reobtain these DDF solely from the MaxEnt principle subject to suitable scale invariant restrictions in all the variables. For the sake of concreteness, we analyse the example of ohmic, fully ionized, tokamak-plasmas, in the weak-collisional transport regime. In this case we show that it is possible to reinterpret the stationary distribution function in terms of the Prigogine distribution function where the logarithm of the DDF is directly linked to the entropy production of the plasma. This leads to the suggestive idea that also the stationary neoclassical distribution functions, for magnetically confined plasmas in the collisional transport regimes, may be derived solely by the MaxEnt principle.

In previous works, we derived stationary density distribution functions (DDF) where the local equilibrium is determined by imposing the maximum entropy (MaxEnt) principle, under the scale invariance restrictions, and the minimum entropy production theorem. In this paper we demonstrate that it is possible to reobtain these DDF solely from the MaxEnt principle subject to suitable scale invariant restrictions in all the variables. For the sake of concreteness, we analyse the example of ohmic, fully ionized, tokamak-plasmas, in the weak-collisional transport regime. In this case we show that it is possible to reinterpret the stationary distribution function in terms of the Prigogine distribution function where the logarithm of the DDF is directly linked to the entropy production of the plasma. This leads to the suggestive idea that also the stationary neoclassical distribution functions, for magnetically confined plasmas in the collisional transport regimes, may be derived solely by the MaxEnt principle., SCOPUS: ar.j, info:eu-repo/semantics/published

Using a new set of flux-forces relations derived in a previous work, the nonlinear contributions to the transport equations, in the several collisional transport regimes (classical, Pfirsch-Schlüter and banana regimes) have been evaluated for fully ionized L-mode tokamak plasmas. We show the expressions for the steady-state particle distribution functions in the several collisional transport regimes. The validity of the nonlinear closure equations, previously derived, has been indirectly tested by checking that the obtained particle distribution functions are indeed solutions of the nonlinear, steady-state, Vlasov-Landau gyro-kinetic equations., http://piers.org/piersproceedings/download.php?file=cGllcnMyMDExTWFycmFrZXNofDNQOV8xODkwLnBkZnwxMDA5MjAxMTUyNDM=, ISSN: 1559-9450, info:eu-repo/semantics/published

Using a new set of flux-forces relations derived in a previous work, the nonlinear contributions to the transport equations, in the several collisional transport regimes (classical, Pfirsch-Schlüter and banana regimes) have been evaluated for fully ionized L-mode tokamak plasmas. We show the expressions for the steady-state particle distribution functions in the several collisional transport regimes. The validity of the nonlinear closure equations, previously derived, has been indirectly tested by checking that the obtained particle distribution functions are indeed solutions of the nonlinear, steady-state, Vlasov-Landau gyro-kinetic equations., http://piers.org/piersproceedings/download.php?file=cGllcnMyMDExTWFycmFrZXNofDNQOV8xODkwLnBkZnwxMDA5MjAxMTUyNDM=, ISSN: 1559-9450, info:eu-repo/semantics/published

An application of the thermodynamic field theory (TFT) to transport processes in L-mode tokamak plasmas is presented. The nonlinear corrections to the linear ("Onsager") transport coefficients in the collisional regimes are derived. A quite encouraging result is the appearance of an asymmetry between the Pfirsch-Schlüter (P-S) ion and electron transport coefficients: the latter presents a nonlinear correction, which is absent for the ions, and makes the radial electron coefficients much larger than the former. Explicit calculations and comparisons between the neoclassical results and the TFT predictions for Joint European Torus (JET) plasmas are also reported. It is found that the nonlinear electron P-S transport coefficients exceed the values provided by neoclassical theory by a factor that may be of the order 102. The nonlinear classical coefficients exceed the neoclassical ones by a factor that may be of order 2. For JET, the discrepancy between experimental and theoretical results for the electron losses is therefore significantly reduced by a factor 102 when the nonlinear contributions are duly taken into account but, there is still a factor of 102 to be explained. This is most likely due to turbulence. The expressions of the ion transport coefficients, determined by the neoclassical theory in these two regimes, remain unaltered. The low-collisional regimes, i.e. the plateau and the banana regimes, are analyzed in the second part of this work. © 2008 American Institute of Physics., SCOPUS: ar.j, info:eu-repo/semantics/published

An application of the thermodynamic field theory (TFT) to transport processes in L-mode tokamak plasmas is presented. The nonlinear corrections to the linear ("Onsager") transport coefficients in the collisional regimes are derived. A quite encouraging result is the appearance of an asymmetry between the Pfirsch-Schlüter (P-S) ion and electron transport coefficients: the latter presents a nonlinear correction, which is absent for the ions, and makes the radial electron coefficients much larger than the former. Explicit calculations and comparisons between the neoclassical results and the TFT predictions for Joint European Torus (JET) plasmas are also reported. It is found that the nonlinear electron P-S transport coefficients exceed the values provided by neoclassical theory by a factor that may be of the order 102. The nonlinear classical coefficients exceed the neoclassical ones by a factor that may be of order 2. For JET, the discrepancy between experimental and theoretical results for the electron losses is therefore significantly reduced by a factor 102 when the nonlinear contributions are duly taken into account but, there is still a factor of 102 to be explained. This is most likely due to turbulence. The expressions of the ion transport coefficients, determined by the neoclassical theory in these two regimes, remain unaltered. The low-collisional regimes, i.e. the plateau and the banana regimes, are analyzed in the second part of this work. © 2008 American Institute of Physics., SCOPUS: ar.j, info:eu-repo/semantics/published

Doctorat en Sciences, info:eu-repo/semantics/nonPublished

It has been shown that the exothermal and isothermal explosive systems are extremely sensitive to fluctuations of either thermodynamical and environmental origin as well as to the way they are initially prepared. The latter source of variability, manifested through small differences in initial conditions, can deeply affect the transient behavior. Applied to an exothermic explosive model, like the Semenov model, the effects of random initial conditions manifest themselves in a wide dispersion of explosion times. Furthermore, under certain conditions the distribution of explosion times becomes bimodal: the initial set of systems split, with the same probability, into a short explosion time class and a long explosion time class. © 1991., SCOPUS: ar.j, info:eu-repo/semantics/published

There are processes in chemical kinetics which, at present, cannot be elucidated in any other way except by comparative analysis between experimental observations and their numerical simulations. This is the case with the Bray-Liebhafsky oscillatory reaction of hydrogen peroxide decomposition. Thus, in the authors' experimental investigation of this reaction it was noticed that the time of appearance of the first maximum of the iodide concentration depends on the initial concentration of hydrogen peroxide in a somewhat unexpected manner. The position of the maximum depends on its rate constant together with the rate constants of other reactions, and also on the ratio between the initial concentrations of the participants in the reaction. In the numerical calculations, the eventual saturation of the solution by oxygen has been taken into account., SCOPUS: ar.j, info:eu-repo/semantics/published

Inclusive charged pion production is studied in an exposure of BEBC, filled with hydrogen, to an incident K+ beam of 70 GeV/c. Total cross sections for pion production and inclusive longitudinal and transverse momentum distributions of π-'s and of positive particles are presented and compared with data at lower energies. Earlier evidence for scaling in the fragmentation regions is confirmed. The central region π- cross section increases proportionally to pLAB-1/4; positive particles show almost no energy dependence at x=0. Particle ratios π+/π- are studied as a function of x and y* and a comparison with 70 GeV/c K-p data is made. Analysis of structure functions for (ππ) pairs and of particle production associated with π± triggers at large, 0, SCOPUS: ar.j, info:eu-repo/semantics/published

Cross sections and charged multiplicity distributions for K+p interactions at 70 GeV/c are presented and compared with K+p data at other energies. Comparisons are also made with available π+p, pp, and K-p data. © 1979 Springer-Verlag., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

Inclusive and semi-inclusive production of Λ and {Mathematical expression} in K+p interactions is studied at an incident momentum of 70 GeV/c. Cross sections and single particle distributions are presented and compared with data at lower energies. Scaling is observed between 32 and 70 GeV/c in the Feynman x variable in the target and the beam fragmentation regions for Λ and {Mathematical expression} inclusive production respectively. An increase of Λ ( {Mathematical expression}) production is observed in the beam (target) fragmentation regions, whereas the data at 70 and 32 GeV/c are reasonably close in the central region. The dependence of the Λ( {Mathematical expression}) polarization as a function of x is measured and found to be in general agreement with the results at 32 GeV/c. The (Λ {Mathematical expression}) pair production cross section increases significantly from 32 to 70 GeV/c. The Λ and {Mathematical expression} production associated with an identified proton is also studied. © 1981 Springer-Verlag., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

The inclusive inelastic processes K+p→pX+ and K+p→Δ++X0 are studied at an incident momentum of 70 GeV/c. The data comes from the Big European Bubble Chamber BEBC filled with hydrogen, exposed to an rf reparated K+ beam at the CERN SPS accelerator. The inclusive cross section for protons with laboratory momentum pLAB≦1.2 GeV/c is equal to (6.1±0.1) mb. Inclusive Δ++-production is studied for, 0, SCOPUS: ar.j, info:eu-repo/semantics/published

We present results on the jet-like properties of multiparticle systems produced in K+p interactions at 70 GeV/c. The data analysed in terms of several variables commonly used to study the jet structure of an event. An extensive comparison is made with jets found in electron-positron annihilations and in deep inelastic νN interactions at comparable energy. Many similarities are found between low-pT jets in this experiment and jets observed in leptonic interactions. Our data are very well reproduced by the Field-Feynman quark fragmentation parametrisation but equally well by a longitudinal phase space model, suggesting that these similarities do not prove or disprove the universal character of the jet fragmentation. © 1981., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

The reaction K+p→Δ++(1236)+ anything is studied at beam momenta 8.2 and 16 GeV/c and compared with other Δ++ producing reactions. We find that the low-mass Δ++π- enhancement affects the shapes of Δ++ inclusive distributions. The triple-Regge formula is found to be consistent with the data. Dual properties of this formula are successfully tested. © 1976., SCOPUS: ar.j, info:eu-repo/semantics/published

Inclusive V0 production in 6.5-GeV/c K-p interactions is studied using the ANL 12-ft-diameter hydrogen bubble chamber. The total cross sections for inclusive K̄0 and Λ0 production are σ(K̄0)=7.98±0.49 mb and σ(Λ0)=3.94±0.24 mb. Semi-inclusive differential cross sections are determined as functions of Feynman x and transverse momentum squared of the V0's and of four-momentum transfer to the V0. The average charge multiplicity, the ratio and the correlation function f2cc for the neutrally charged hadronic system recoiling from the V0 are determined as functions of the mass of the recoiling system. Results are used to examine universal aspects of multiparticle production. © 1979 The American Physical Society., SCOPUS: ar.j, info:eu-repo/semantics/published

Inclusive production of Λ and Λ in K+ p interactions is studied at incident momenta of 8.2 and 16.0 GeV/c. Cross sections and single-particle distributions are presented, the correlation between longitudinal and transverse momentum is investigated, and the dependence of average charge multiplicity on missing mass measured. For Λ production, early scaling is observed in the target fragmentation region when the data are presented in terms of (M2-Mth2)/s and t, where Mth is the threshold value of the missing mass M. Furthermore, a triple-Regge analysis in these variable yields an effective exchange trajectory which passes through the K, Q and L mesons. There is evidence for beam fragmentation in Λ and Λ production, but the contributions seem not to be dominant in the fragmentation region. Nevertheless, the parameter values in a triple-Regge description are estimated, and together with those for target fragmentation in Λ production, provide a complete description of the fragmentation contributions to the two reactions. Integration of the resultant distribution functions over the complete Chew-Low plot yields fragmentation cross sections increasing approximately as log s; in addition the observed features of the x, pL and pT2 projections and of the pL-pT correlation are well-described in the fragmentation regions. Central production contributions are isolated by subtracting the calculated fragmentation distributions. © 1976., SCOPUS: ar.j, info:eu-repo/semantics/published

We present a systematic analysis of the production of K*+(892) and Δ++(1236) resonances in the K+p → K0pπ+ reaction at 5, 8.25 and 16 GeV/c. We have measured total cross sections, differential cross sections, density matrix elements and examined resonance production mechanisms in terms of the exchange of states with definite naturality. Some results on the reaction K+p → K*+(1420)p are also given. © 1976., SCOPUS: ar.j, info:eu-repo/semantics/published

We present the first spin-parity analysis of the K+K+K-) system produced in the reaction K+p → K+K+K-p, and show that the general features of this system resemble those of the (ππ+π-) and Kπ+π-) systems produced in the reactions π(K)p → π(K)π+π-p. There is a low mass enhancement, (47 ± 11)% of which corresponds to 1+ states decaying to Kø. At higher (K+K+K-) masses 2- → Kf′ becomes increasingly significant and at all masses there is a 0- contribution of roughly 30%. © 1975., SCOPUS: ar.j, info:eu-repo/semantics/published

The reaction K-d→K-π+π-d has been studied at an incident K--momentum of 4.5 GeV/c. A fractional analysis has been performed. A spin density matrix analysis and a partial wave analysis indicate that the events in the Q-region mainly originate from {Mathematical expression} production in a JPℓmη=(1+S0+) wave state. A comparison has been made with the reaction K+d→K+π-π+d at 4.6 GeV/c and the combined results have been compared to K+/-p→K+/-π+π-p at 13 GeV/c. It is found that the Kππ-mass spectra produced on a proton or deuteron target can be described by one single Deck type mechanism on which direct Q-meson production is superimposed. © 1980 Springer-Verlag., SCOPUS: ar.j, info:eu-repo/semantics/published

Results are presented concerning K-d and K-n elastic scattering at an incident momentum of 4.5 GeV/c. The high-energy Glauber formalism has been used in analyzing the data in which the nucleon scattering amplitudes are parameterized and employing the spherical and quadrupole deuteron form factors. An impulse approximation analysis of the K-n differential scattering cross section fitted to a single exponential of the form dσ/dt)0eBt, leads to the result (dσ/dt)0 = 21.3 + mn; 5.5 mb/(GeV/c)2and B = 6.9 + mn; 0.5 (GeV/c)-2. A global fit has been made to existing K + mn;N two-body scattering data at this energy in order to determine the scattering amplitudes. It was found that the K-n and K-p elastic amplitudes are dominantly imaginary with a relatively small contribution from spin-flip amplitudes. The slopes of the differential elastic cross sections for K-n and K-p are nearly equal, as are those for K + n and K + p. However, the value of the slope for K + is smaller than that for K- at this energy. © 1977., SCOPUS: ar.j, info:eu-repo/semantics/published

The cross sections for the reactions: (a) K+p → K+pπ+π-π+ and (b) K+p → K+π+π+π-n have been determined at 8.2 and 16 GeV/c with the following results: at 8.2 GeV/c: (a) 0.99 ± 0.07 mb, (b) 0.41 ± 0.04 mb; at 16 GeV/c: (a) 0.72 ± 0.05 mb, (b) 0.28 ± 0.05 mb. Using the available data at other energies, the cross-section dependence of these reactions on the incident momentum is discussed. © 1976., SCOPUS: ar.j, info:eu-repo/semantics/published

In this paper a comparison of the general features of the reactions K±p→Q±p (1) at incident momentum 8.25 GeV/c is presented. The relevant data derive from events yielding four-constraint fits to the reactions K±p→K±π+π-p in exposures of the CERN 2m HBC to RF-separated K+ and K- beams. The (Kππ) effective mass distributions, production angular distributions in the Q region (1.2≤M(Kππ)≤1.5 GeV) and corresponding decay angular distributions are exhibited, and background effects due to N* and Δ production are systematically studied. In particular, it is found that the distributions dσ/dt′ and dσ/dt for reactions (1) are adequately described by exponential functions over the interval 0.05-0.35 GeV2, and exhibit a cross-over effect for momentum transfer squared -0.1 GeV2. For both reactions a flattening of dσ/dt′ for t′ < 0.05 GeV2 is observed. By studying the Chew-Low plots and the effects of the different cuts it was found that this flattening cannot be attributed to amplitudes with net s-channel helicity flip different from zero, at least at these energies. © 1976., SCOPUS: ar.j, info:eu-repo/semantics/published

A sample of 3414 events of the type K-p →K-pπ+ π- were recorded in the ANL 12-foot hydrogen bubble chamber exposed to a K--meson beam of 6.5 GeV/c momentum. The total cross section for this reaction (1.17±0.07 mb), is compared to data obtained at neighbouring energies. Resonance production is studied using two complementary procedures; an analytical multichannel fit and multidimensional cluster methods. Baryon exchange processes, accounting for approximately 5% of the data, are isolated by the latter method. © 1983 Springer-Verlag., SCOPUS: ar.j, info:eu-repo/semantics/published

The inclusive production of neutral kaons in 70 GeV/c K+p interactions is studied with the CERN BEBC bubble chamber. The (semi-)inclusive cross sections are interpreted in terms of the various strangeness channels leading to neutral kaon production. The invariant inclusive cross section for kaon production is studied as a function of pt2 and the Feynman variable x. The latter distributions are considered both "raw" and corrected for the presence of K0's resulting from K* decay. They are compared with the predictions expected from the Regge-Mueller formalism, the recombination model and fragmentation models. © 1981., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

SCOPUS: ar.j, info:eu-repo/semantics/published

The inclusive reactions K+p → K0 + X++ at 5.0 and 8.2 GeV/c and K+p → K0 + π+ + X+ at 8.2 GeV/c are analysed in terms of angular variables θ and ø. The data are compared and found consistent with various theoretical bounds on the s-dependence of the inclusive reaction cross sections. Experimental evidence is presented that dσ/dcos θ = a exp (-b sinθ) with b ∼ √s and a increasing with energy. Correlations between the angular variables and between the variable ø and the K0 and π+ momenta in the c.m.s. are observed and discussed. © 1972., SCOPUS: ar.j, info:eu-repo/semantics/published

The elastic scattering of K+ mesons on protons is studied at 3.5 and 5 GeV/c. The total elastic cross-sections are found to be (4.36±0.36) mb and (3.82±0.41) mb respectively. The differential elastic cross-sections, which exhibit characteristic diffraction peaks, are fitted by dσ/d t=(dσ/d t)0 e αt, giving α=(3.85±0.12) and (4.70±0.21) (GeV/c)-2 for the two momenta respectively, with, SCOPUS: ar.j, info:eu-repo/semantics/published