# PLASMA EFFECTS ON FAST PAIR BEAMS IN COSMIC VOIDS

## Abstract

The interaction of TeV gamma rays from distant blazars with the extragalactic background light produces relativistic electron-positron pair beams by the photon- photon annihilation process. The created pair beam distribution is unstable to linear two-stream instabilities of both electrostatic and electromagnetic nature in the unmagnetized intergalactic medium (IGM). The maximum electrostatic growth rate occurs at angles of 39.{sup 0}2 with respect to the pair beam direction, and is more than three orders of magnitude greater than the maximum Weibel growth rate, indicating that the linear oblique electrostatic instability operates much faster than the Weibel instability. The dissipation of the generated electrostatic turbulence is different for intense and weak gamma-ray blazars. For intense blazars, the normalized number of generated pairs n {sub 22} = n{sub b} /[10{sup -22} cm{sup -3}] exceeds the critical density n{sub c} (T) = 4.8 Multiplication-Sign 10{sup -3} T {sub 4} for given normalized IGM temperature T {sub 4} = T/[10{sup 4} K] necessary for the onset of the modulation instability, so that all free kinetic pair energy is dissipated in heating the IGM in cosmic voids. For weak blazars, half of the initial energy density of the beam particles is transferred to the electrostatic and electromagneticmore »

- Authors:

- Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

- Publication Date:

- OSTI Identifier:
- 22086513

- Resource Type:
- Journal Article

- Journal Name:
- Astrophysical Journal

- Additional Journal Information:
- Journal Volume: 758; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANNIHILATION; ASTROPHYSICS; BREMSSTRAHLUNG; COMPTON EFFECT; COSMIC ELECTRONS; COSMIC PHOTONS; COSMIC POSITRONS; COSMOLOGY; ENERGY DENSITY; ENERGY LOSSES; FLUCTUATIONS; FLUX DENSITY; GAMMA RADIATION; PLASMA; QUASARS; RELATIVISTIC RANGE; TEV RANGE; TURBULENCE; TWO-STREAM INSTABILITY; VOIDS

### Citation Formats

```
Schlickeiser, R., Ibscher, D., and Supsar, M., E-mail: rsch@tp4.rub.de, E-mail: ibscher@tp4.rub.de, E-mail: markus.supsar@rub.de.
```*PLASMA EFFECTS ON FAST PAIR BEAMS IN COSMIC VOIDS*. United States: N. p., 2012.
Web. doi:10.1088/0004-637X/758/2/102.

```
Schlickeiser, R., Ibscher, D., & Supsar, M., E-mail: rsch@tp4.rub.de, E-mail: ibscher@tp4.rub.de, E-mail: markus.supsar@rub.de.
```*PLASMA EFFECTS ON FAST PAIR BEAMS IN COSMIC VOIDS*. United States. doi:10.1088/0004-637X/758/2/102.

```
Schlickeiser, R., Ibscher, D., and Supsar, M., E-mail: rsch@tp4.rub.de, E-mail: ibscher@tp4.rub.de, E-mail: markus.supsar@rub.de. Sat .
"PLASMA EFFECTS ON FAST PAIR BEAMS IN COSMIC VOIDS". United States. doi:10.1088/0004-637X/758/2/102.
```

```
@article{osti_22086513,
```

title = {PLASMA EFFECTS ON FAST PAIR BEAMS IN COSMIC VOIDS},

author = {Schlickeiser, R. and Ibscher, D. and Supsar, M., E-mail: rsch@tp4.rub.de, E-mail: ibscher@tp4.rub.de, E-mail: markus.supsar@rub.de},

abstractNote = {The interaction of TeV gamma rays from distant blazars with the extragalactic background light produces relativistic electron-positron pair beams by the photon- photon annihilation process. The created pair beam distribution is unstable to linear two-stream instabilities of both electrostatic and electromagnetic nature in the unmagnetized intergalactic medium (IGM). The maximum electrostatic growth rate occurs at angles of 39.{sup 0}2 with respect to the pair beam direction, and is more than three orders of magnitude greater than the maximum Weibel growth rate, indicating that the linear oblique electrostatic instability operates much faster than the Weibel instability. The dissipation of the generated electrostatic turbulence is different for intense and weak gamma-ray blazars. For intense blazars, the normalized number of generated pairs n {sub 22} = n{sub b} /[10{sup -22} cm{sup -3}] exceeds the critical density n{sub c} (T) = 4.8 Multiplication-Sign 10{sup -3} T {sub 4} for given normalized IGM temperature T {sub 4} = T/[10{sup 4} K] necessary for the onset of the modulation instability, so that all free kinetic pair energy is dissipated in heating the IGM in cosmic voids. For weak blazars, half of the initial energy density of the beam particles is transferred to the electrostatic and electromagnetic fluctuations on timescales smaller than the inverse Compton energy loss timescale of the pairs. In both cases, this prevents the development of a full electromagnetic pair cascade as in vacuum. For weak blazars, the superluminal electrostatic fluctuations are dissipated by the inverse Compton scattering into transverse electromagnetic waves by the relaxed relativistic pair particles to optical frequencies, implying the occurrence of optical electrostatic bremsstrahlung pair halos from weak blazars with spectral flux densities below 50 {mu}Jy.},

doi = {10.1088/0004-637X/758/2/102},

journal = {Astrophysical Journal},

issn = {0004-637X},

number = 2,

volume = 758,

place = {United States},

year = {2012},

month = {10}

}