Acceleration of ACRs at the termination shock: 2-AD simulations

József Kóta, J. Randy Jokipii

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

When Voyagers' crossed the termination shock (TS) in 2004 and 2007 the spectrum of anomalous cosmic rays (ACRs) did not unfold to a smooth power law at the shock. ACR uxes continued to increase into the heliosheath and ACR spectra unfolded gradually as Voyagers advanced deeper into the heliosheath. This finding can be interpreted in terms of field-topology, i.e the connection between the Parker spiral field and the blunt termination shock. We consider a two-dimensional model with an offset circle representing the blunt termination shock. Field lines wound in a Parker spiral cross the TS multiple times. We present simulation results with changing the shock strength and injection rate along the shock. We find that the flux of few MeV ACRs turn out sensitive to the injection rate at the nose and quite insensitive to the injection rate at the flank and tail regions. We also perform a backward calculation tracing the history of few MeV ACRs. Our results indicate that most of these ACRs, including ACRs in the tail, were likely be injected at the nose of the TS.

Original languageEnglish (US)
Title of host publication31st International Cosmic Ray Conference, ICRC 2009
PublisherUniversity of Lodz
StatePublished - 2009
Event31st International Cosmic Ray Conference, ICRC 2009 - Lodz, Poland
Duration: Jul 7 2009Jul 15 2009

Other

Other31st International Cosmic Ray Conference, ICRC 2009
CountryPoland
CityLodz
Period7/7/097/15/09

Fingerprint

cosmic rays
shock
simulation
injection
tracing
two dimensional models
topology
histories

Keywords

  • Acceleration
  • Anomalous cosmic rays
  • Termination shock

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

Kóta, J., & Jokipii, J. R. (2009). Acceleration of ACRs at the termination shock: 2-AD simulations. In 31st International Cosmic Ray Conference, ICRC 2009 University of Lodz.

Acceleration of ACRs at the termination shock : 2-AD simulations. / Kóta, József; Jokipii, J. Randy.

31st International Cosmic Ray Conference, ICRC 2009. University of Lodz, 2009.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Kóta, J & Jokipii, JR 2009, Acceleration of ACRs at the termination shock: 2-AD simulations. in 31st International Cosmic Ray Conference, ICRC 2009. University of Lodz, 31st International Cosmic Ray Conference, ICRC 2009, Lodz, Poland, 7/7/09.
Kóta J, Jokipii JR. Acceleration of ACRs at the termination shock: 2-AD simulations. In 31st International Cosmic Ray Conference, ICRC 2009. University of Lodz. 2009
Kóta, József ; Jokipii, J. Randy. / Acceleration of ACRs at the termination shock : 2-AD simulations. 31st International Cosmic Ray Conference, ICRC 2009. University of Lodz, 2009.
@inproceedings{7bf3d968da08470f999d0d4d7bd7ec49,
title = "Acceleration of ACRs at the termination shock: 2-AD simulations",
abstract = "When Voyagers' crossed the termination shock (TS) in 2004 and 2007 the spectrum of anomalous cosmic rays (ACRs) did not unfold to a smooth power law at the shock. ACR uxes continued to increase into the heliosheath and ACR spectra unfolded gradually as Voyagers advanced deeper into the heliosheath. This finding can be interpreted in terms of field-topology, i.e the connection between the Parker spiral field and the blunt termination shock. We consider a two-dimensional model with an offset circle representing the blunt termination shock. Field lines wound in a Parker spiral cross the TS multiple times. We present simulation results with changing the shock strength and injection rate along the shock. We find that the flux of few MeV ACRs turn out sensitive to the injection rate at the nose and quite insensitive to the injection rate at the flank and tail regions. We also perform a backward calculation tracing the history of few MeV ACRs. Our results indicate that most of these ACRs, including ACRs in the tail, were likely be injected at the nose of the TS.",
keywords = "Acceleration, Anomalous cosmic rays, Termination shock",
author = "J{\'o}zsef K{\'o}ta and Jokipii, {J. Randy}",
year = "2009",
language = "English (US)",
booktitle = "31st International Cosmic Ray Conference, ICRC 2009",
publisher = "University of Lodz",

}

TY - GEN

T1 - Acceleration of ACRs at the termination shock

T2 - 2-AD simulations

AU - Kóta, József

AU - Jokipii, J. Randy

PY - 2009

Y1 - 2009

N2 - When Voyagers' crossed the termination shock (TS) in 2004 and 2007 the spectrum of anomalous cosmic rays (ACRs) did not unfold to a smooth power law at the shock. ACR uxes continued to increase into the heliosheath and ACR spectra unfolded gradually as Voyagers advanced deeper into the heliosheath. This finding can be interpreted in terms of field-topology, i.e the connection between the Parker spiral field and the blunt termination shock. We consider a two-dimensional model with an offset circle representing the blunt termination shock. Field lines wound in a Parker spiral cross the TS multiple times. We present simulation results with changing the shock strength and injection rate along the shock. We find that the flux of few MeV ACRs turn out sensitive to the injection rate at the nose and quite insensitive to the injection rate at the flank and tail regions. We also perform a backward calculation tracing the history of few MeV ACRs. Our results indicate that most of these ACRs, including ACRs in the tail, were likely be injected at the nose of the TS.

AB - When Voyagers' crossed the termination shock (TS) in 2004 and 2007 the spectrum of anomalous cosmic rays (ACRs) did not unfold to a smooth power law at the shock. ACR uxes continued to increase into the heliosheath and ACR spectra unfolded gradually as Voyagers advanced deeper into the heliosheath. This finding can be interpreted in terms of field-topology, i.e the connection between the Parker spiral field and the blunt termination shock. We consider a two-dimensional model with an offset circle representing the blunt termination shock. Field lines wound in a Parker spiral cross the TS multiple times. We present simulation results with changing the shock strength and injection rate along the shock. We find that the flux of few MeV ACRs turn out sensitive to the injection rate at the nose and quite insensitive to the injection rate at the flank and tail regions. We also perform a backward calculation tracing the history of few MeV ACRs. Our results indicate that most of these ACRs, including ACRs in the tail, were likely be injected at the nose of the TS.

KW - Acceleration

KW - Anomalous cosmic rays

KW - Termination shock

UR - http://www.scopus.com/inward/record.url?scp=84899046611&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84899046611&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:84899046611

BT - 31st International Cosmic Ray Conference, ICRC 2009

PB - University of Lodz

ER -