Effects of interplanetary transport on derived energetic particle source strengths

We study the transport of solar energetic particles (SEPs) in the inner heliosphere in order to relate observations made by an observer at 1 AU to the number and total energy content of accelerated particles at the source, assumed to be near the Sun. We use a numerical simulation that integrates the trajectories of a large number of individual particles moving in the interplanetary magnetic field. We model pitch angle scattering and adiabatic cooling of energetic ions with energies from 50 keV nucleon^(−1) to 100 MeV nucleon^(−1). Among other things, we determine the number of times that particles of a given energy cross 1 AU and the average energy loss that they suffer because of adiabatic deceleration in the solar wind. We use a number of different forms of the interplanetary spatial diffusion coefficient and a wide range of scattering mean-free paths and consider a number of different ion species in order to generate a wide range of simulation results that can be applied to individual SEP events. We apply our simulation results to observations made at 1 AU of the 20 February 2002 solar energetic particle event, finding the original energy content of several species. We find that estimates of the source energy based on SEP measurements at 1 AU are relatively insensitive to the mean-free path and scattering scheme if adiabatic cooling and multiple crossings are taken into account

Options for transporting Russian gas to Western Europe: A game-theoretic simulation analysis

This paper examines the perspectives of Russian gas exports to Western Europe and the strategic options of the CIS gas transiting countries, namely Ukraine and Belarus. The development of a new transit corridor through Belarus (the Yamal-Europe pipeline), depriving Ukraine of its former monopoly, has modified the situation profoundly. The thrust of the paper is an analysis of nthe strategies that Ukraine and Belarus may pursue in transiting Russian gas: non-cooperative duopoly, cooperative duopoly, and individual or collective cooperation with Russia. Using a demand function for Western European gas imports from Russia, we estimate prices and quantities for gas transit, the expected profits for Russia, Ukraine, and Belarus, and the resulting import prices for Western Europe. The results indicate that Ukraine suffers a loss of several hundred million USD annually from the market entry of Belarus, Belarus has an incentive to increase its gas transit capacity to at least 56 billion cubic meters, and Russia's profits increase, in particular when it unites its gas sector with Belarus and Ukraine. For Western Europe, all scenarios indicate an increase in welfare through the new pipeline, but also an increasing importance of gas imports from Russia. -- Der Beitrag untersucht die Perspektiven russischer Gasexporte nach Westeuropa und die strategischen Optionen der Gastransitländer Ukraine und Belarus. Durch den Neu- und Ausbau eines Gastransitkorridors durch Belarus (die Jamal-Europa-Pipeline) geht die bisherige Monopolstellung der Ukraine als Transitland verloren. Ziel der Arbeit ist die Modellierung und Quantifizierung unterschiedlicher Wettbewerbsstrategien, wie das nichtkooperative Duopol, das kooperative Duopol, oder die individuelle bzw. kollektive Kooperation der Transitländer mit Russland. Hierfür werden Exportpreise und mengen sowie die resultierenden Gewinne der Spieler geschätzt. Durch den Markteintritt von Belarus ergeben sich erhebliche Verluste für die Ukraine, während sich Belarus mit einem Ausbau seiner Kapazitäten auf 56 Mrd. m3 noch besser stellt. Russlands Gewinne steigen insbesondere durch die vertikale Integration der belarussischen und ukrainischen Gassektoren. Für Westeuropa legen die Ergebnisse erhebliche Wohlfahrtsgewinne durch den Pipelineausbau nahe, gleichzeitig aber auch eine gestiegene Abhängigkeit von Gasimporten aus Russland.Gas,pipelines,strategic behavior,CIS,Russia

\u3csup\u3e12\u3c/sup\u3eC/\u3csup\u3e13\u3c/sup\u3eC Ratio in Planetary Nebulae from the \u3cem\u3eIUE\u3c/em\u3e Archives

We investigated the abundance ratio of 12C/13C in planetary nebulae by examining emission lines arising from C III 2s2p3Po2,1,0 → 2s21S0. Spectra were retrieved from the International Ultraviolet Explorer archives, and multiple spectra of the same object were co-added to achieve improved signal-to-noise ratio. The 13C hyperfine structure line at 1909.6 Å was detected in NGC 2440. The 12C/13C ratio was found to be ~4.4+/-1.2. In all other objects, we provide an upper limit for the flux of the 1910 Å line. For 23 of these sources, a lower limit for the 12C/13C ratio was established. The impact on our current understanding of stellar evolution is discussed. The resulting high-signal-to-noise ratio C III spectrum helps constrain the atomic physics of the line formation process. Some objects have the measured 1907/1909 Å flux ratio outside the low-electron density theoretical limit for 12C. A mixture of 13C with 12C helps to close the gap somewhat. Nevertheless, some observed 1907/1909 Å flux ratios still appear too high to conform to the currently predicted limits. It is shown that this limit, as well as the 1910/1909 Å flux ratio, are predominantly influenced by using the standard partitioning among the collision strengths for the multiplet 1S0-3PoJ according to the statistical weights. A detailed calculation for the fine-structure collision strengths between these individual levels would be valuable

Nonlinear electron-phonon coupling in doped manganites

We employ time-resolved resonant x-ray diffraction to study the melting of charge order and the associated insulator-metal transition in the doped manganite Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ after resonant excitation of a high-frequency infrared-active lattice mode. We find that the charge order reduces promptly and highly nonlinearly as function of excitation fluence. Density functional theory calculations suggest that direct anharmonic coupling between the excited lattice mode and the electronic structure drive these dynamics, highlighting a new avenue of nonlinear phonon control

12^{12}C/13^{13}C ratio in planetary nebulae from the IUE archives

We investigated the abundance ratio of $^{12}$C/$^{13}$C in planetary nebulae by examining emission lines arising from \ion{C}{3} 2s2p ^3P_{2,1,0} \to 2s^2 ^1S_0. Spectra were retrieved from the International Ultraviolet Explorer archives, and multiple spectra of the same object were coadded to achieve improved signal-to-noise. The $^{13}$C hyperfine structure line at 1909.6 \AA was detected in NGC 2440. The $^{12}$C/$^{13}$C ratio was found to be $\sim4.4\pm$1.2. In all other objects, we provide an upper limit for the flux of the 1910 \AA line. For 23 of these sources, a lower limit for the $^{12}$C/$^{13}$C ratio was established. The impact on our current understanding of stellar evolution is discussed. The resulting high signal-to-noise \ion{C}{3} spectrum helps constrain the atomic physics of the line formation process. Some objects have the measured 1907/1909 flux ratio outside the low-electron density theoretical limit for $^{12}$C. A mixture of $^{13}$C with $^{12}$C helps to close the gap somewhat. Nevertheless, some observed 1907/1909 flux ratios still appear too high to conform to the presently predicted limits. It is shown that this limit, as well as the 1910/1909 flux ratio, are predominantly influenced by using the standard partitioning among the collision strengths for the multiplet $^1S_0$--$^3P_J$ according to the statistical weights. A detailed calculation for the fine structure collision strengths between these individual levels would be valuable.Comment: ApJ accepted: 19 pages, 3 Figures, 2 Table

How efficient are coronal mass ejections at accelerating solar energetic particles?

The largest solar energetic particle (SEP) events are thought to be due to particle acceleration at a shock driven by a fast coronal mass ejection (CME). We investigate the efficiency of this process by comparing the total energy content of energetic particles with the kinetic energy of the associated CMEs. The energy content of 23 large SEP events from 1998 through 2003 is estimated based on data from ACE, GOES, and SAMPEX, and interpreted using the results of particle transport simulations and inferred longitude distributions. CME data for these events are obtained from SOHO. When compared to the estimated kinetic energy of the associated coronal mass ejections (CMEs), it is found that large SEP events can extract ~10% or more of the CME kinetic energy. The largest SEP events appear to require massive, very energetic CMEs

Reduced CO\u3csub\u3e2\u3c/sub\u3e/O\u3csub\u3e2\u3c/sub\u3e specificity of ribulose-bisphosphate carboxylase/oxygenase in a temperature-sensitive chloroplast mutant of \u3ci\u3eChlamydomonas\u3c/i\u3e

The Chlamydomonas reinhardtii chloroplast mutant 68-4PP is phenotypically indistinguishable from wild type at 25°C but fails to grow photosynthetically at 35°C. It had about 30% of the wild-type level of ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) holoenzyme and carboxylase activity when grown at 25°C, but less than 15% when grown at 35°C. Pulse-labeling with 35S showed that the decrease in enzyme level at the restrictive temperature was not a result of reduced synthesis of enzyme subunits. The CO2/O2 specificity factor (VcKo/VoKc, where Vc and Vo are Vmax values for carboxylation and oxygenation and Kc and Ko are Km values for CO2 and 02) of the mutant enzyme was found to be significantly less than that of the wild-type enzyme (54 ± 2 and 62 ± 1, respectively), and this alteration was accompanied by increases in Ko and Kc and a decrease in Vc/Vo. DNA sequencing revealed a single missense mutation in the 684PP chloroplast large-subunit gene. This mutation causes leucine to be replaced by phenylalanine at position 290 in the large subunit polypeptide sequence. These results (i) support previous studies that implicated this region of the large subunit as an important structural component of the enzyme\u27s function and (ii) demonstrate that chloroplast genetic modification of the CO2/O2 specificity factor of a plant-type carboxylase/oxygenase is feasible