Recent results in cosmic ray physics and their interpretation

Author: Blasi, P.

arXiv: 1312.1590

reported by Zhang Xiao

1. Introduction

2. Status of the SNR paradigm

3. Spectral breaks

4. CR acceleration in partially ionized media and Balmer line emission in SNRs

5. summary

Outline

1. Introduction

2. Status of the SNR paradigm

particles are accelerated at SNR with spectral index of α

E dependent diffusive propagation with

observed CRs with spectral index α + δ ~ 2.7

◆ SNR paradigm

the test particle theory of particle acceleration: α = 2

δ = 0.7 ?

anisotropy

2. Status of the SNR paradigm

predictions of NLDSA:

1. concave-shap spectrum

2. decrease the T of downstream gas

3. CR-induced plasma instabilities

standard DSA

efficient

2. Status of the SNR paradigm

Escaping

When, How ... ...

◆ B-field amplification

2. Status of the SNR paradigm

Why ?

1. to explain the thin nonthermal X-ray rims in virtually all young SNRs.

2. let maximum energy close to the knee energy.

How ?

1. due to plasma related phenomena if the shock propagates in an inhomogeneous medium.

2. CR-induced magnetic field amplification

2. Status of the SNR paradigm

◆ test of the SNR paradigm: gamma-rays emission

I) the SNR-MCs system

II) the young individual SNRs

example: RX J1713.7-3946 and Tycho

3. Spectral breaks

Adriani, O. et al. 2011, Sci, 332, 69

PAMELA and CREAM

80GV < Ф < 232 GVα: 2.85 ± 0.015 ± 0.004

Ф > 232 GV

α: 2.67 ± 0.03 ± 0.05

80GV < Ф < 240 GV

α: 2.766 ± 0.01±0.027

Ф > 240 GV

α: 2.477±0.06±0.03

Helium

Proton

◆ Observed results

1. both spectra have a break at rigidity ~ 230-240 GV

2. the spectrum of He is systematically harder than the p spectrum.

3. Spectral breaks

● not confirmed by AMS-02 !

● supported by the analysis of the gamma ray spectrum of gamma rays from MCs in the Gould belt.

confirmed by AMS-02

3. Spectral breaks

1. local source Thoudam and Horandel 2012, MNRAS, 421, 1209 Thoudam and Horandel arXiv 1304.1400

2. NLDSA at FS and RS Ptuskin et al, 2013, ApJ, 763, 5

3. propagation effects I) D(E) → D(x, E) Tomassetti, T. 2012, ApJL, 752, L13 II) pre-existing turbulence + self-generated turbulence Blasi, p. et al, 2012, SPhReL, 109, 61

4. dispersion in the spectral indices Yuan et al. 2011, PhReD, 84, 043002

Interpretation:

4. CR acceleration in partially ionized media and Balmer line emission in SNRs

collisionless shock

upstream downstream

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neutral hydrogen with low T

ionized hydrogen with low T+

neutral hydrogen with high T

T ↑

T→

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+exchange e-

broad Balmer line

narrow Balmer line

ionized hydrogen with high T+

◆ Balmer line emission

4. CR acceleration in partially ionized media and Balmer line emission in SNRs

collisionless shock

upstream downstream

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neutral hydrogen with low T

ionized hydrogen with low T+

neutral hydrogen with high T

T ↑

T→

+

+exchange e-

broad Balmer line

narrow Balmer line

ionized hydrogen with high T+

New phenomena under the condition of efficient acceleration

1. decrease the T of the gas downstream

2. A precursor is formed upstream

narrow the broad Balmer line

broaden the narrow Balmer line

◆ Balmer line emission

4. CR acceleration in partially ionized media and Balmer line emission in SNRs

◆ Shape of the Balmer line emission

4. CR acceleration in partially ionized media and Balmer line emission in SNRs

collisionless shock

upstream downstream

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neutral return flux ! reduce Mach number

◆ Modification caused by neutral gas

intermediate Balmer line

4. CR acceleration in partially ionized media and Balmer line emission in SNRs

◆ Example: SNR 0509-67.5

Thank You !

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