Voyager energetic particle observations at interplanetary shocks and upstream of planetary bow shocks: 1977?1990

1992 ◽  
Vol 59 (1-2) ◽  
pp. 167-201 ◽  
Author(s):  
S. M. Krimigis
Keyword(s):  
Energetic Particle ◽  
Interplanetary Shocks ◽  
Bow Shocks

Bow Shocks In The Solar Wind: Lessons Towards Understanding Interplanetary Shocks

2010 ◽  
Author(s):  
Xochitl Blanco-Cano ◽  
M. Maksimovic ◽  
K. Issautier ◽  
N. Meyer-Vernet ◽  
M. Moncuquet ◽  
...  
Keyword(s):  
Solar Wind ◽  
Interplanetary Shocks ◽  
Bow Shocks

scholarly journals Solar cycle variations of the energetic H/He intensity ratio at high heliolatitudes and in the ecliptic plane

2003 ◽  
Vol 21 (6) ◽  
pp. 1229-1243 ◽  
Author(s):  
D. Lario ◽  
E. C. Roelof ◽  
R. B. Decker ◽  
G. C. Ho ◽  
C. G. Maclennan ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Intensity Ratio ◽  
Energetic Particle ◽  
Solar Minimum ◽  
High Speed ◽  
Solar Maximum ◽  
Ecliptic Plane ◽  
Interplanetary Shocks ◽  
Interplanetary Physics

Abstract. We study the variability of the heliospheric energetic proton-to-helium abundance ratios during different phases of the solar cycle. We use energetic particle, solar wind, and magnetic field data from the Ulysses, ACE and IMP-8 spacecraft to compare the H/He intensity ratio at high heliographic latitudes and in the ecliptic plane. During the first out-of-ecliptic excursion of Ulysses (1992–1996), the HI-SCALE instrument measured corotating energetic particle intensity enhancements characterized by low values (< 10) of the 0.5–1.0 MeV nucleon-1 H/He intensity ratio. During the second out-of-ecliptic excursion of Ulysses (1999–2002), the more frequent occurrence of solar energetic particle events resulted in almost continuously high (< 20) values of the H/He ratio, even at the highest heliolatitudes reached by Ulysses. Comparison with in-ecliptic measurements from an identical instrument on the ACE spacecraft showed similar H/He values at ACE and Ulysses, suggesting a remarkable uniformity of energetic particle intensities in the solar maximum heliosphere at high heliolatitudes and in the ecliptic plane. In-ecliptic observations of the H/He intensity ratio from the IMP-8 spacecraft show variations between solar maximum and solar minimum similar to those observed by Ulysses at high heliographic latitudes. We suggest that the variation of the H/He intensity ratio throughout the solar cycle is due to the different level of transient solar activity, as well as the different structure and duration that corotating solar wind structures have under solar maximum and solar minimum conditions. During solar minimum, the interactions between the two different types of solar wind streams (slow vs. fast) are strong and long-lasting, allowing for a continuous and efficient acceleration of interstellar pickup He +. During solar maximum, transient events of solar origin (characterized by high values of the H/He ratio) are able to globally fill the heliosphere. In addition, during solar maximum, the lack of strong recurrent high-speed solar wind streams, together with the dynamic character of the Sun, lead to weak and short-lived solar wind stream interactions. This results in a less efficient acceleration of pickup He +, and thus a higher value of the H/He intensity ratio.Key words. Interplanetary physics (energetic particles, interplanetary shocks; solar wind plasma)

scholarly journals Fluxes and fluences of SEP events derived from SOLPENCO

2005 ◽  
Vol 23 (9) ◽  
pp. 3047-3053 ◽  
Author(s):  
A. Aran ◽  
B. Sanahuja ◽  
D. Lario
Keyword(s):  
Energetic Particle ◽  
Radial Distance ◽  
Solar Energetic Particle ◽  
Particle Energy ◽  
Particle Accelerator ◽  
Large Set ◽  
The Sun ◽  
Particle Engineering ◽  
Interplanetary Shocks ◽  
Peak Flux

Abstract. We have developed aran04 a tool for rapid predictions of proton flux and fluence profiles observed during gradual solar energetic particle (SEP) events and upstream of the associated traveling interplanetary shocks. This code, named SOLPENCO (for SOLar Particle ENgineering COde), contains a data base with a large set of interplanetary scenarios under which SEP events develop. These scenarios are basically defined by the solar longitude of the parent solar activity, ranging from E75 to W90, and by the position of the observer, located at 0.4 AU or at 1.0 AU, from the Sun. We are now analyzing the performance and reliability of SOLPENCO. We address here two features of SEP events especially relevant to space weather purposes: the peak flux and the fluence. We analyze how the peak flux and the fluence of the synthetic profiles generated by SOLPENCO vary as a function of the strength of the CME-driven shock, the heliolongitude of the solar parent activity and the particle energy considered. In particular, we comment on the dependence of the fluence on the radial distance of the observer (which does not follow an inverse square law), and we draw conclusions about the influence of the shock as a particle accelerator in terms of its evolving strength and the heliolongitude of the solar site where the SEP event originated.

Characteristics of energetic particle events associated with interplanetary shocks

1985 ◽  
Vol 90 (A1) ◽  
pp. 12-18 ◽  
Author(s):  
K.-P. Wenzel ◽  
R. Reinhard ◽  
T. R. Sanderson ◽  
E. T. Sarris
Keyword(s):  
Energetic Particle ◽  
Interplanetary Shocks
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