scholarly journals Characteristics of <u>></u> 290 keV magnetosheath ions

1999 ◽  
Vol 17 (5) ◽  
pp. 650-658 ◽  
Author(s):  
I. Karanikola ◽  
G. C. Anagnostopoulos ◽  
A. Rigas
Keyword(s):  
Statistical Analysis ◽  
Shock Waves ◽  
Space Plasma ◽  
High Energy ◽  
Bow Shock ◽  
Occurrence Frequency ◽  
Space Plasma Physics ◽  
Energetic Ions ◽  
Time Periods ◽  
Statistical Results

Abstract. We performed a statistical analysis of 290-500 keV ion data obtained by IMP-8 during the years 1982-1988 within the earth's magnetosheath and analysed in detail some time periods withdistinct ion bursts. These studies reveal the following characteristics for magnetosheath 290-500 keV energetic ions: (a) the occurrence frequency and the flux of ions increase with increasing geomagnetic activity as indicated by the Kp index; the occurrence frequency was found to be as high as P > 42% for Kp > 2, (b) the occurrence frequency in the dusk magnetosheath was found to be slightly dependent on the local time and ranged between ~30% and ~46% for all Kp values; the highest occurrence frequency was detected near the dusk magnetopause (21 LT), (c) the high energy ion bursts display a dawn-dusk asymmetry in their maximum fluxes, with higher fluxes appearing in the dusk magnetosheath, and (d) the observations in the dusk magnetosheath suggest that there exist intensity gradients of energetic ions from the bow shock toward the magnetopause. The statistical results are consistent with the concept that leakage of magnetospheric ions from the dusk magnetopause is a semi-permanent physical process often providing the magnetosheath with high energy (290-500 keV) ions.Key words. Magnetospheric physics (magnetosheath; planetary magnetospheres). Space plasma physics (shock waves).

scholarly journals Spatial distribution of upstream magnetospheric ≥50 keV ions

2000 ◽  
Vol 18 (1) ◽  
pp. 42-46 ◽  
Author(s):  
G. C. Anagnostopoulos ◽  
G. Argyropoulos ◽  
G. Kaliabetsos
Keyword(s):  
Solar Wind ◽  
Statistical Analysis ◽  
Wind Speed ◽  
Solar Wind Speed ◽  
Bow Shock ◽  
Occurrence Frequency ◽  
Ion Distributions ◽  
Interplanetary Physics ◽  
Earth’S Bow Shock ◽  
Bow Shocks

Abstract. We present for the first time a statistical study of \\geq50 keV ion events of a magnetospheric origin upstream from Earth's bow shock. The statistical analysis of the 50-220 keV ion events observed by the IMP-8 spacecraft shows: (1) a dawn-dusk asymmetry in ion distributions, with most events and lower intensities upstream from the quasi-parallel pre-dawn side (4 LT-6 LT) of the bow shock, (2) highest ion fluxes upstream from the nose/dusk side of the bow shock under an almost radial interplanetary magnetic field (IMF) configuration, and (3) a positive correlation of the ion intensities with the solar wind speed and the index of geomagnetic index Kp, with an average solar wind speed as high as 620 km s-1 and values of the index Kp > 2. The statistical results are consistent with (1) preferential leakage of ~50 keV magnetospheric ions from the dusk magnetopause, (2) nearly scatter free motion of ~50 keV ions within the magnetosheath, and (3) final escape of magnetospheric ions from the quasi-parallel dawn side of the bow shock. An additional statistical analysis of higher energy (290-500 keV) upstream ion events also shows a dawn-dusk asymmetry in the occurrence frequency of these events, with the occurrence frequency ranging between ~16%-~34% in the upstream region.Key words. Interplanetary physics (energetic particles; planetary bow shocks)

scholarly journals F. Curtis Michel (1934–2015)

Eos ◽  
2015 ◽  
Vol 96 ◽  
Author(s):  
Paul Cloutier ◽  
Alexander Dessler ◽  
Thomas Hill ◽  
Richard Wolf
Keyword(s):  
Plasma Physics ◽  
Air Force ◽  
Space Plasma ◽  
High Energy ◽  
Planetary Science ◽  
Space Science ◽  
Science Department ◽  
Space Plasma Physics ◽  
High Energy Astrophysics ◽  
Rice University

A veteran Air Force pilot who cofounded the Space Science Department at Rice University, Michel contributed to high-energy astrophysics, space plasma physics, and planetary science.

scholarly journals The occurrence frequency of upward ion beams in the auroral zone as a function of altitude using Polar/TIMAS and DE-1/EICS data

2003 ◽  
Vol 21 (10) ◽  
pp. 2059-2072 ◽  
Author(s):  
P. Janhunen ◽  
A. Olsson ◽  
W. K. Peterson
Keyword(s):  
Particle Flux ◽  
Ion Beam ◽  
Radial Distance ◽  
Space Plasma ◽  
Auroral Zone ◽  
Ion Beams ◽  
Occurrence Frequency ◽  
Space Plasma Physics ◽  
Wave Heating ◽  
Auroral Phenomena

Abstract. We study the occurrence frequency of upward auroral ion beams as a function of altitude using three years of  Polar/TIMAS ion data combined with 11 years of DE-1/ EICS ion data, in order to reach a complete altitude coverage between 5000 and 30 000 km. The most interesting result is that there is a peak in ion beam occurrence frequency and invariant energy flux and invariant particle flux at ¢ 3 RE radial distance. The peak exists at about the same altitude in both the evening and midnight MLT sectors. No solar cycle effects are found. We suggest that the peak could be due to a preferred altitude of auroral potential structures at ¢ 3 RE . To substantiate the suggestion, we also present a simple Monte Carlo simulation of ion beams. Another result is that the ion beam occurrence frequency and invariant (mapped to ionospheric altitude) energy and particle fluxes increase in the radial distance range 4–6 RE , suggesting that wave heating processes may take place in this altitude range.Key words. Magnetospheric physics (auroral phenomena; magnetosphere-ionosphere interactions) – Space plasma physics (charged particle motion and acceleration)

Influence of Nd:YAG Laser Irradiation on an Adhesive Restorative Procedure

2006 ◽  
Vol 31 (5) ◽  
pp. 604-609 ◽  
Author(s):  
M. Franke ◽  
A. W. Taylor ◽  
A. Lago ◽  
M. C. Fredel
Keyword(s):  
Statistical Analysis ◽  
Bond Strength ◽  
Laser Irradiation ◽  
Significant Influence ◽  
Nd:Yag Laser ◽  
Deleterious Effect ◽  
Adhesive System ◽  
High Energy ◽  
Low Energy ◽  
Adhesive Penetration

Clinical Relevance Statistical analysis of the results obtained in this study shows that Nd:YAG laser irradiation on the adhesive system has a significant influence on bond strength to dentin. Bond strength is improved by better adhesive penetration when low energy is applied; whereas, high energy densities have a deleterious effect on the procedure.

Damaging effects of high energy shock waves on cultured Madin Darby Canine Kidney (MDCK) cells

1990 ◽  
Vol 18 (4) ◽  
pp. 255-258 ◽  
Author(s):  
W. L. Strohmaier ◽  
K. -H. Bichler ◽  
P. Deetjen ◽  
S. Kleinknecht ◽  
M. Pedro ◽  
...  
Keyword(s):  
Shock Waves ◽  
Mdck Cells ◽  
High Energy ◽  
Madin Darby Canine Kidney ◽  
Darby Canine Kidney ◽  
Canine Kidney ◽  
Damaging Effects

scholarly journals The Influence of Design Parameters on Straight Bevel Gear Dynamics

2015 ◽  
Vol 5 (2) ◽  
pp. 114
Author(s):  
Chiu-Fan Hsieh ◽  
You-Qing Zhu
Keyword(s):  
Statistical Analysis ◽  
The Other ◽  
Design Parameters ◽  
Bevel Gears ◽  
Straight Bevel Gear ◽  
Pressure Angle ◽  
Stress Fluctuation ◽  
Shaft Angle ◽  
Statistical Results ◽  
Component Force

<p class="1Body">This study analyzes the influence of design parameters on the dynamics of straight bevel gears by constructing a model that allows variation in the shaft angle, pressure angle, and backlash. According to the statistical analysis, the order of influence of these parameters on weight is shaft angle &gt; pressure angle &gt; backlash. When the shaft angle is 90°, the statistical results show the drive is stable and the stress fluctuation level is low. The pressure angle, on the other hand, can affect the gear’s dynamic property by influencing the driving component force on the gear and the component force on the shaft. The results for the shaft and pressure angles are used to determine the appropriate backlash. Overall, the analysis not only provides designers with an important reference but explains the dominance in the market of gear designs with a 90° shaft angle and a 20° pressure angle.</p>

scholarly journals Structure of the heliosheath from HSTOF energetic neutral atoms measurements

2018 ◽  
Vol 618 ◽  
pp. A26 ◽  
Author(s):  
A. Czechowski ◽  
M. Hilchenbach ◽  
K. C. Hsieh ◽  
M. Bzowski ◽  
S. Grzedzielski ◽  
...  
Keyword(s):  
Energy Range ◽  
Ecliptic Plane ◽  
High Energy ◽  
Neutral Atoms ◽  
Ion Distribution ◽  
Ion Density ◽  
Heliospheric Observatory ◽  
Energetic Neutral Atoms ◽  
Time Periods ◽  
Ecliptic Longitude

Context. From the year 1996 until now, High energy Suprathermal Time Of Flight sensor (HSTOF) on board Solar and Heliospheric Observatory (SOHO) has been measuring the heliospheric energetic neutral atoms (ENA) flux between ±17° from the ecliptic plane. At present it is the only ENA instrument with the energy range within that of Voyager LECP energetic ion measurements. The energetic ion density and thickness of the inner heliosheath along the Voyager 1 trajectory are now known, and the ENA flux in the HSTOF energy range coming from the Voyager 1 direction may be estimated. Aims. We use HSTOF ENA data and Voyager 1 energetic ion spectrum to compare the regions of the heliosheath observed by HSTOF and Voyager 1. Methods. We compared the HSTOF ENA flux data from the forward and flank sectors of the heliosphere observed in various time periods between the years 1996 and 2010 and calculated the predicted ENA flux from the Voyager 1 direction using the Voyager 1 LECP energetic ion spectrum and including the contributions of charge exchange with both neutral H and He atoms. Results. The ratio between the HSTOF ENA flux from the ecliptic longitude sector 210−300° (the LISM apex sector) for the period 1996−1997 to the estimated ENA flux from the Voyager 1 direction is ∼1.3, but decreases to ∼0.6 for the period 1996−2005 and ∼0.3 for 1998−2006. For the flank longitude sectors (120−210° and 300−30°), the ratio also tends to decrease with time from ∼0.6 for 1996−2005 to ∼0.2 for 2008−2010. We discuss implications of these results for the energetic ion distribution in the heliosheath and the structure of the heliosphere.

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