1. A Knee in the cosmic ray energy spectrum: A pulsar, supernova origin?
ICRC 2011 Beijing
A Knee in the cosmic ray energy spectrum:
A pulsar, supernova origin?
Tadeusz Wibig (Lodz, Poland) and Arnold Wolfendale (Durham, Uk).

2. Hu, H-B etal. (2009 and later) have proposed that the knee at 3PeV is due to CR from pulsars interacting with optical radiation from the associated young SN. This is the PSNR model.

3. Absorption length vs energy for P and Fe interacting with photons (1 eV cm-3 for all but CMB)

4. The reduction factor (for protons) and sharpness.

5. A problem: pulsar keeps going after (young) SNR has ceased emitting radiation.

6. ‘source activity’: time pulsar is ‘on’ %: fraction of SNR radiation absorbed by shell.

7. Early interactions of pulsar –CR with SN ejecta.
Other problems:
Early interactions of pulsar –CR with SN ejecta.
Mass composition of CR quite different from that expected from the model.
Could a ‘magnetar’ be responsible?
Characteristics not appropriate (B,P).
Nearest is 3.5 Kpc away – too far.

8. Conclusions:
PSNR model unlikely to be valid.
Single source (SNR) model seems more likely.