Role of microscopic plasma instabilities on shock dissipation process

2009 ◽  
Author(s):  
N. Shimada ◽  
M. Hoshino ◽  
Masfumi Hirahara ◽  
Yoshizumi Miyoshi ◽  
Naoki Terada ◽  
...  
Keyword(s):  
Plasma Instabilities ◽  
Dissipation Process ◽  
Shock Dissipation

scholarly journals Role of Plasma Instabilities in Auroral Phenomena

Nature ◽  
1965 ◽  
Vol 205 (4975) ◽  
pp. 998-998 ◽  
Author(s):  
BRUNO COPPI
Keyword(s):  
Plasma Instabilities ◽  
Auroral Phenomena

scholarly journals Cluster and Double Star observations of dipolarization

2005 ◽  
Vol 23 (8) ◽  
pp. 2915-2920 ◽  
Author(s):  
R. Nakamura ◽  
W. Baumjohann ◽  
T. L. Zhang ◽  
C. M. Carr ◽  
A. Balogh ◽  
...  
Keyword(s):  
Local Time ◽  
Double Star ◽  
Propagation Direction ◽  
Dissipation Process ◽  
Analysis Techniques ◽  
Point Analysis ◽  
Time Sector ◽  
Local Time Sector ◽  
The Imf

Abstract. We studied two types of dipolarization events with different IMF conditions when Cluster and Double Star (TC-1) were located in the same local time sector: 7 August 2004, 18:00-24:00 UT, during a disturbed southward/northward IMF interval, and 14 August 2004, 21:00-24:00 UT, when the IMF was stably northward. Cluster observed dipolarization as well as fast flows during both intervals, but this was not the case for TC-1. For both events the satellites crossed near the conjugate location of the MIRACLE stations. By using multi-point analysis techniques, the direction/speed of the propagation is determined using Cluster and is then compared with the disturbances at TC-1 to discuss its spatial/temporal scale. The propagation direction of the BZ disturbance at Cluster was mainly dawnward with a tailward component for 7 August and with a significant Earthward component for 14 August associated with fast flows. We suggest that the role of the midtail fast flows can be quite different in the dissipation process depending on the condition of the IMF and resultant configuration of the tail.

scholarly journals Photoprotection through ultrafast charge recombination in photochemical reaction centres under oxidizing conditions

2017 ◽  
Vol 372 (1730) ◽  
pp. 20160378 ◽  
Author(s):  
Fei Ma ◽  
David J. K. Swainsbury ◽  
Michael R. Jones ◽  
Rienk van Grondelle
Keyword(s):  
Charge Separation ◽  
Radical Pair ◽  
Physiological Role ◽  
Spectral Evolution ◽  
Dissipation Process ◽  
Reaction Centres ◽  
Membrane Spanning ◽  
Lipid Nanodiscs ◽  
Natural Photosynthesis

Engineering natural photosynthesis to address predicted shortfalls in food and energy supply requires a detailed understanding of its molecular basis and the intrinsic photoprotective mechanisms that operate under fluctuating environmental conditions. Long-lived triplet or singlet excited electronic states have the potential to cause photodamage, particularly in the presence of oxygen, and so a variety of mechanisms exist to prevent formation of such states or safely dissipate their energy. Here, we report a dramatic difference in spectral evolution in fully reduced and partially oxidized Rhodobacter sphaeroides reaction centres (RCs) following excitation of the monomeric bacteriochlorophyll (BChl) cofactors at 805 nm. Three types of preparation were studied, including RCs purified as protein/lipid nanodiscs using the copolymer styrene maleic acid. In fully reduced RCs such excitation produces membrane-spanning charge separation. In preparations of partially oxidized RCs the spectroscopic signature of this charge separation is replaced by that of an energy dissipation process, including in the majority sub-population of reduced RCs. This process, which appears to take place on both cofactor branches, involves formation of a BChl + /bacteriopheophytin − radical pair that dissipates energy via recombination to a vibrationally hot ground state. The possible physiological role of this dissipative process under mildly oxidizing conditions is considered. This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’.

DE-2 cusp observations: Role of plasma instabilities in topside ionospheric heating and density fluctuations

1982 ◽  
Vol 9 (9) ◽  
pp. 997-1000 ◽  
Author(s):  
S. A. Curtis ◽  
W. R. Hoegy ◽  
L. H. Brace ◽  
N. C. Maynard ◽  
M. Suguira ◽  
...  
Keyword(s):  
Density Fluctuations ◽  
Plasma Instabilities ◽  
Ionospheric Heating
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