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ÖÐÎÄ°æ Location: Homepage >> Fan Guo : CV - Publications - Blog

Space & Solar Physics 202

Poster:

1. [Tutorials] Energetic particles in Heliosphere
This tutorial intends to introduce the basics of energetic particle, also reflect some recent aspects. I will maintain and update the content.

All the comments and suggestions are welcome.
Directly reply or send an email to guofan.ustc@gmail.com

Recommended materials:
Reames, D.V. 1999 Space Science Review
link: http://adsabs.harvard.edu/abs/1999SSRv...90..413R

Longair, M.S., High Energy Astrophysics: Volume 2
link: search on google book or buy online at amazon.

----
to be updated
http://adsabs.harvard.edu/abs/2002SSRv..101....1A
http://adsabs.harvard.edu/abs/2005ApJ...625..474T
http://adsabs.harvard.edu/abs/2000ApJ...532L..79M
http://adsabs.harvard.edu/abs/2000JGR...10525079Z
http://adsabs.harvard.edu/abs/2006JGRA..11107S08B
http://adsabs.harvard.edu/abs/2002ApJ...572L.103G
http://adsabs.harvard.edu/abs/2005ApJS..158...38L
http://adsabs.harvard.edu/abs/2003ApJ...588.1149D
http://adsabs.harvard.edu/abs/2004ApJ...605..902C
Fan Guo
Posted at 2008-07-05 13:33 CST
Last modified at 2010-12-25 07:38 CST
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2. Overview 1
Spectrum of Energetic Particles (Oxygen nuclei, as an example)

Figure 1  


ESP - energetic storm particles: Particles with relatively low energies seen close to the shock region.
SEP - solar energetic particles
CIR particles - particles accelerated in corotating interaction region
ACR anomalous cosmic rays - coming from the outer heliosphere, usually believed to be energized by termination shock
GCR galactic cosmic rays - coming from outside of the solar system, believed to be accelerated by supernova remnants.

The remarkable feature of cosmic rays (energetic charged particles) is that they appear to be power-law at high energy.





Figure 2  


Species and Sites:

Most of energetic particles can be identified to be associated with shock waves.
Solar energetic particles - coronal shocks (with particles from flares as a uncertainty)
Energetic storm particles - interplanetary shocks or CIR shocks.
anomalous cosmic rays - the termination shock
galactic cosmic rays - supernova shock waves

Download images (local images only) as a tar.gz pack: Full Size Small Size
Fan Guo
Posted at 2008-07-05 13:36 CST
Last modified at 2010-12-25 07:47 CST
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3. Overview 2
Energetic particles associated with CME.
Remark:
1. CMEs produce highest energetic particles in heliosphere (sometimes ~10GeV)
2. The main accelerator is shocks driven by fast propagating CMEs.
3. Note the peak in energy flux associated with shock.
4. The standard acceleration mechanism is diffusive shock acceleration (DSA), sometimes called first-order Fermi process.


Figure 1

Fan Guo
Posted at 2008-07-06 03:05 CST
Last modified at 2008-07-11 08:51 CST
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4. Overview 3
* 1. Particle acceleration in flares producing bremsstrahlung emission
Remarks:
a. Acceleration of particles in flares is not well understood. Shocks, reconnections and waves (stochastic process) may all play certain role.
b. Note distinct components of emission produced by thermal (in loops) and non-thermal (at footpoints) bremsstrahlung.

Figure 1
















* 2. Some of particles can escape into interplanetary space

Figure 2


Download images (local images only) as a tar.gz pack: Full Size Small Size
Fan Guo
Posted at 2008-07-07 01:02 CST
Last modified at 2008-07-11 08:10 CST
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5. Overview 4
Particle acceleration in CIRs
a. CIRs are formed due to fast stream of solar wind pursuing slow wind.
b. Shocks again dominate the acceleration process in CIRs

Figure 1  

Fan Guo
Posted at 2008-07-07 02:25 CST
Last modified at 2008-07-11 08:16 CST
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6. Overview 5
* Anomalous Cosmic Rays.
Most people believe anomalous cosmic rays are pickup ions accelerated at termination shock by diffusive acceleration process. However, Voyager 1 and Voyager 2 didn't see ACR peaks at termination shock, which indicates current theory need to be revised. A major idea is that one has to consider temporal variation or spatial variation in diffusive shock acceleration (Florinski & Zank 2005, Schwadron & McComas 2006, Kota & Jokipii 2008, Jokipii & Kota 2008, Guo, Jokipii & Kota 2010). Other ideas include stochastic acceleration (Fisk & Gloecker) and particle acceleration at reconnection site (Drake & Opher; Lazarian & Opher)
See pictures in Overview 1 for a first sense.

* Galactic Cosmic Rays (GCR)
Supernova Remnants are thought to be the main source of GCR.

[1]
Fan Guo
Posted at 2008-07-07 03:08 CST
Last modified at 2010-12-25 16:43 CST
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