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| 2. |
- CAIRNS, RA, et al.
(författare)
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ELECTROSTATIC SOLITARY STRUCTURES IN NONTHERMAL PLASMAS
- 1995
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Ingår i: GEOPHYSICAL RESEARCH LETTERS. - : AMER GEOPHYSICAL UNION. - 0094-8276. ; 22:20, s. 2709-2712
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Solitary electrostatic structures involving density depletions have been observed in the upper ionosphere by the Freja satellite [Dovner el al., 1994]. If these are interpreted as ion sound solitons, the difficulty arises that the standard Korteweg-de Vri
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| 3. |
- Clark, DW, et al.
(författare)
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Associations of autozygosity with a broad range of human phenotypes
- 2019
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 4957-
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Tidskriftsartikel (refereegranskat)abstract
- In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (FROH) for >1.4 million individuals, we show that FROH is significantly associated (p < 0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: FROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44–66%] in the odds of having children. Finally, the effects of FROH are confirmed within full-sibling pairs, where the variation in FROH is independent of all environmental confounding.
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| 5. |
- Dieckmann, Mark E, 1969-, et al.
(författare)
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Particle-in-cell simulations of electron acceleration by a simple capacitative antenna in collisionless plasma
- 2004
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 109:A12
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Tidskriftsartikel (refereegranskat)abstract
- We examine the electron acceleration by a localized electrostatic potential oscillating at high frequencies by means of particle-in-cell (PIC) simulations, in which we apply oscillating electric fields to two neighboring simulation cells. We derive an analytic model for the direct electron heating by the externally driven antenna electric field, and we confirm that it approximates well the electron heating obtained in the simulations. In the simulations, transient waves accelerate electrons in a sheath surrounding the antenna. This increases the Larmor radii of the electrons close to the antenna, and more electrons can reach the antenna location to interact with the externally driven fields. The resulting hot electron sheath is dense enough to support strong waves that produce high-energy sounder-accelerated electrons (SAEs) by their nonlinear interaction with the ambient electrons. By increasing the emission amplitudes in our simulations to values that are representative for the ones of the sounder on board the OEDIPUS C (OC) satellites, we obtain electron acceleration into the energy range which is comparable to the 20 keV energies of the SAE observed by the OC mission. The emission also triggers stable electrostatic waves oscillating at frequencies close to the first harmonic of the electron cyclotron frequency. We find this to be an encouraging first step of examining SAE generation with kinetic numerical simulation codes.
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| 6. |
- Misra, Amar P, et al.
(författare)
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Nonlinear wave-wave interactions in quantum plasmas
- 2010
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Ingår i: New frontiers in advanced plasma physics. - : American Institute of Physics (AIP). - 9780735408623 ; , s. 103-110
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Konferensbidrag (refereegranskat)abstract
- Wave-wave interaction in plasmas is a topic of important research since the 16th century. The formation of Langmuir solitons through the coupling of high-frequency (hf) Langmuir and low-frequency (If) ion-acoustic waves, is one of the most interesting features in the context of turbulence in modern plasma physics. Moreover, quantum plasmas, which are ubiquitous in ultrasmall electronic devices, micromechanical systems as well as in dense astrophysical environments are a topic of current research. In the light of notable interests in such quantum plasmas, we present here a theoretical investigation on the nonlinear interaction of quantum Langmuir waves (QLWs) and quantum ion-acoustic waves (QIAWs), which are governed by the one-dimensional quantum Zakharov equations (QZEs). It is shown that a transition to spatiotemporal chaos (STC) occurs when the length scale of excitation of linear modes is larger than that of the most unstable ones. Such length scale is, however, to be larger (compared to the classical one) in presence of the quantum tunneling effect. The latter induces strong QIAW emission leading to the occurrence of collision and fusion among the patterns at an earlier time than the classical case. Moreover, numerical simulation of the QZEs reveals that many solitary patterns can be excited and saturated through the modulational instability (MI) of unstable harmonic modes. In a longer time, these solitons are seen to appear in the state of STC due to strong QIAW emission as well as by the collision and fusion in stochastic motion. The energy in the system is thus strongly redistributed, which may switch on the onset of Langmuir turbulence in quantum plasmas.
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| 7. |
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| 8. |
- Onishchenko, OG, et al.
(författare)
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Locality of ion-drift wave spectra in weakly-turbulent dusty plasmas
- 2001
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Ingår i: PHYSICS OF PLASMAS. - : AMER INST PHYSICS. - 1070-664X. ; 8:11, s. 5045-5048 Language: English
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Tidskriftsartikel (refereegranskat)abstract
- The locality of weakly turbulent Kolmogorov spectra for the ion-drift waves in dusty plasmas and the flute waves in electron-ion plasmas is analyzed. Using a standard kinetic approach for the description of the wave turbulence it is shown that the wave sp
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| 9. |
- Onishchenko, OG, et al.
(författare)
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Nonlinear ion-drift waves in a nonuniform plasma with nonzero ion-temperature-gradient effects
- 2001
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Ingår i: PHYSICS OF PLASMAS. - : AMER INST PHYSICS. - 1070-664X. ; 8:1, s. 59-66 Language: English
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that Grad hydrodynamics dan be used for the description of nonlinear ion-drift waves in a low beta plasma. The set of nonlinear equations which allows us to describe both the ion polarization drift and the nonzero ion Larmor;radius effects is
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