Acceleration of the anomalous component of cosmic rays revisited

Kallenbach, R.; Bamert, K.; Hilchenbach, M.

doi:10.5194/astra-5-49-2009

Cited by 4 publications

(7 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, there is the local ion injection efficiency describing the percentage of pick-up ions locally entering into the Fermi-1 shock acceleration process due to repeated back-and forth-scatterings between upstream and downstream flow conditions at the shock. (see Kucharek & Scholer 1995;Chalov & Fahr 1996;Giacalone & Jokipii 1999;McComas & Schwadron 2006;Kallenbach et al 2009), and second, we also consider the total local upstream pick-up ion flux Φ i, s arriving at the shock. This finally results in…”

Section: Injection To Puis From the Acr-regimementioning

confidence: 99%

The inner heliospheric source for keV-energetic IBEX ENAs

Fahr

Siewert

McComas

et al. 2011

A&A

View full text Add to dashboard Cite

Context. Up to now, three succesive full-sky maps of heliospheric fluxes of KeV-energetic neutral H-atoms have been registered with the satellite IBEX. The most outstanding feature persisting in these maps is the so-called ribbon which appears as an arc around the upwind direction with unexpectedly high fluxes. This radiation feature was not predicted by models, but at present is tentatively explained as due to energetic plasma sites outside the heliosphere in regions beyond the heliopause. Aims. Since all these proposed explanations, however, need to rely on unproven energizing ion processes, we shall investigate in this article alternative ion sources of keV-ENAs that in contrast appear much closer to the sun, but are based on a clear concept of ion energization to KeV energies, namely suprathermal pick-up ions at a few AU inside and outside of the solar wind termination shock. Methods. Using well-established models for the solar wind magnetic field and the heliospheric TS surface, we derive skymaps of the magnetic field tilt angle, the resulting injection efficiency and the resulting ENA flows. The results are normalised to the ion flux observations made by Voyager-1. We also discuss basic modifications of the TS geometry within the framework of the model. Results. We calculate ENA fluxes of these pick-up ions and show that they, due to their sensitivities to magnetic tilt angles at the termination shock surface, reveal a radiative sickle feature around the upwind direction which in many of its properties resembles the ENA ribbon feature seen by IBEX, although the highest IBEX intensities do not seem to be quantitatively representable by our calculations.

show abstract

Section: Injection To Puis From the Acr-regimementioning

confidence: 99%

The inner heliospheric source for keV-energetic IBEX ENAs

Fahr

Siewert

McComas

et al. 2011

A&A

View full text Add to dashboard Cite

show abstract

“…(29). The positive root of this equa tion s 0 determines the slope of the accelerated particle spectrum.…”

Section: Anisotropy Of Angular Distribution Of Particlesmentioning

confidence: 98%

“…(29) at negative values of the variable s, we obtain the solution in the form of the following series when calculating the res idues of the integrand at the points s n ,…”

Section: Spatial and Energy Distributions Of Particlesmentioning

confidence: 99%

“…The shock wave bounding the supersonic solar wind can effectively accelerate superwarm charged particles and anomalous cosmic rays [1,25,29,38,40]. The anomalous CRs represent atoms of interstellar medium that are ionized in the inner heliosphere then carried out by the solar wind into the outer heliosphere and accelerated by the heliospheric shock wave and, probably, by electromag netic fields of the heliomantle [21,25,29,33]. …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Charged particle acceleration in the front of the shock wave bounding supersonic solar wind

Fedorov

2014

Kinemat. Phys. Celest. Bodies

View full text Add to dashboard Cite

The process of cosmic ray acceleration in the front of the spherical shock wave bounding the supersonic solar wind is studied. On the basis of our analytical solution of the transport equation, the energy and spatial distributions of cosmic ray intensity and anisotropy are investigated. It is shown that the shape of accelerated particle spectrum is determined by the medium compressibility at the shock front and by cosmic ray modulation parameters. Fig. 6. Spatial distribution of cosmic rays. J + is the flux of high energy particles, Jis the flux of low energy particles, and J is the flux of cosmic rays (σ = 3 and μ = μ 1 = 5). Fig. 7. Dependence of the energy flux of cosmic rays on the heliocentric distance at σ = 3, μ = μ 1 = 5, and E k0 = 100 MeV.

show abstract

“…The long‐awaited crossings of the TS by the Voyager 1 (V2) and 2 (V2) spacecraft have led to a revisitation of this classical ACR paradigm, as the ACR spectra at the TS were not of the expected form [e.g., Decker et al , 2005]. A multitude of different theories have emerged to account for this discrepancy, most notably adiabatic heating [e.g., Langner et al , 2006a; Zhang , 2006], Fermi II (stochastic) acceleration [e.g., Zhang , 2006; Ferreira et al , 2007; Kallenbach et al , 2009], energy cascade processes [e.g., Fisk and Gloeckler , 2009; Jokipii and Lee , 2010], preferred regions of acceleration [e.g., McComas and Schwadron , 2006; Jokipii and Kóta , 2008; Ngobeni and Potgieter , 2008; Strauss et al , 2010b], and magnetic reconnections near the heliopause [e.g., Drake et al , 2010] or a combination of these processes, all of which occur inside the heliosheath. As such, the modulation of ACRs in the outer heliosphere is at the moment a very contentious subject.…”

Section: Introductionmentioning

confidence: 99%

Modeling anomalous cosmic ray oxygen gradients over successive solar cycles

Strauss

Potgieter

2010

J. Geophys. Res.

View full text Add to dashboard Cite

[1] Cosmic ray drift directions depend both on the charge of the particle population under consideration, as well as the heliospheric magnetic field polarity which oscillates within a ∼22 year cycle. The differences in the cosmic ray drift patterns between successive solar cycles manifest themselves in the sign of the latitudinal cosmic ray gradient. For positively charged particles, a positive latitudinal gradient is expected in the qA > 0 polarity cycle, while a negative value is expected in the qA < 0 cycle. For the first time observed radial and latitudinal values for anomalous cosmic ray oxygen are available in both of these cycles. In the present qA < 0 cycle, the observations seem, however, inconsistent with the drift-dominated considerations discussed above, as the latitudinal gradient is smaller than expected and perhaps even positive. This issue is addressed by using a comprehensive numerical model for anomalous cosmic ray acceleration and transport, based on new diffusion coefficients, to simulate these gradients over the previous two magnetic polarity cycles. Computed gradients and energy spectra (at Earth and at Ulysses) are compared to observations, with good agreement achieved between observations and model predictions. For the qA > 0 cycle, the model predicts a positive latitudinal gradient but for the qA < 0 cycle a latitudinal gradient that is smaller and that can be either positive or negative. It is concluded that drifts and poleward diffusion set up competing latitudinal gradients in the qA < 0 cycle, with the resulting sign of the gradient determined by the most effective of the two processes.Citation: Strauss, R. D., and M. S. Potgieter (2010), Modeling anomalous cosmic ray oxygen gradients over successive solar cycles,

show abstract

Acceleration of the anomalous component of cosmic rays revisited

Cited by 4 publications

References 45 publications

The inner heliospheric source for keV-energetic IBEX ENAs

The inner heliospheric source for keV-energetic IBEX ENAs

Charged particle acceleration in the front of the shock wave bounding supersonic solar wind

Modeling anomalous cosmic ray oxygen gradients over successive solar cycles

Contact Info

Product

Resources

About