Home > Research > Publications & Outputs > Solar Energetic Particles (SEP) and Galactic Co...

Electronic data

  • 1-s2.0-S0019103517303615-main

    Rights statement: This is the author’s version of a work that was accepted for publication in Icarus. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Icarus, 300, 2017 DOI: 10.1016/j.icarus.2017.08.040

    Accepted author manuscript, 5.24 MB, PDF document

    Available under license: CC BY-NC-ND: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License

Links

Text available via DOI:

View graph of relations

Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR) as tracers of solar wind conditions near Saturn: event lists and applications

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Published

Standard

Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR) as tracers of solar wind conditions near Saturn: event lists and applications. / Roussos, E.; Jackman, C.M.; Thomsen, M.F. et al.
In: Icarus, Vol. 300, 15.01.2018, p. 47-71.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Harvard

Roussos, E, Jackman, CM, Thomsen, MF, Kurth, WS, Badman, SV, Paranicas, C, Kollmann, P, Krupp, N, Bučík, R, Mitchell, DG, Krimigis, SM, Hamilton, DC & Radioti, A 2018, 'Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR) as tracers of solar wind conditions near Saturn: event lists and applications', Icarus, vol. 300, pp. 47-71. https://doi.org/10.1016/j.icarus.2017.08.040

APA

Roussos, E., Jackman, C. M., Thomsen, M. F., Kurth, W. S., Badman, S. V., Paranicas, C., Kollmann, P., Krupp, N., Bučík, R., Mitchell, D. G., Krimigis, S. M., Hamilton, D. C., & Radioti, A. (2018). Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR) as tracers of solar wind conditions near Saturn: event lists and applications. Icarus, 300, 47-71. https://doi.org/10.1016/j.icarus.2017.08.040

Vancouver

Roussos E, Jackman CM, Thomsen MF, Kurth WS, Badman SV, Paranicas C et al. Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR) as tracers of solar wind conditions near Saturn: event lists and applications. Icarus. 2018 Jan 15;300:47-71. Epub 2017 Sept 1. doi: 10.1016/j.icarus.2017.08.040

Author

Roussos, E. ; Jackman, C.M. ; Thomsen, M.F. et al. / Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR) as tracers of solar wind conditions near Saturn : event lists and applications. In: Icarus. 2018 ; Vol. 300. pp. 47-71.

Bibtex

@article{3703059a958f4707a421901deda46160,
title = "Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR) as tracers of solar wind conditions near Saturn: event lists and applications",
abstract = "The lack of an upstream solar wind monitor poses a major challenge to any study that investigates the influence of the solar wind on the configuration and the dynamics of Saturn{\textquoteright}s magnetosphere. Here we show how Cassini MIMI/LEMMS observations of Solar Energetic Particle (SEP) and Galactic Cosmic Ray (GCR) transients, that are both linked to energetic processes in the heliosphere such us Interplanetary Coronal Mass Ejections (ICMEs) and Corotating Interaction Regions (CIRs), can be used to trace enhanced solar wind conditions at Saturn{\textquoteright}s distance. SEP protons can be easily distinguished from magnetospheric ions, particularly at the MeV energy range. Many SEPs are also accompanied by strong GCR Forbush Decreases. GCRs are detectable as a low count-rate noise signal in a large number of LEMMS channels. As SEPs and GCRs can easily penetrate into the outer and middle magnetosphere, they can be monitored continuously, even when Cassini is not situated in the solar wind. A survey of the MIMI/LEMMS dataset between 2004 and 2016 resulted in the identification of 46 SEP events. Most events last more than two weeks and have their lowest occurrence rate around the extended solar minimum between 2008 and 2010, suggesting that they are associated to ICMEs rather than CIRs, which are the main source of activity during the declining phase and the minimum of the solar cycle. We also list of 17 time periods ( >  50 days each) where GCRs show a clear solar periodicity ( ∼ 13 or 26 days). The 13-day period that derives from two CIRs per solar rotation dominates over the 26-day period in only one of the 17 cases catalogued. This interval belongs to the second half of 2008 when expansions of Saturn{\textquoteright}s electron radiation belts were previously reported to show a similar periodicity. That observation not only links the variability of Saturn{\textquoteright}s electron belts to solar wind processes, but also indicates that the source of the observed periodicity in GCRs may be local. In this case GCR measurements can be used to provide the phase of CIRs at Saturn. We further demonstrate the utility of our survey results by determining that: (a) Magnetospheric convection induced by solar wind disturbances associated with SEPs is a necessary driver for the formation of transient radiation belts that were observed throughout Saturn{\textquoteright}s magnetosphere on several occasions during 2005 and on day 105 of 2012. (b) An enhanced solar wind perturbation period that is connected to an SEP of day 332/2013 was the definite source of a strong magnetospheric compression which led to open flux loading in the magnetotail. Finally, we propose how the event lists can define the basis for single case studies or statistical investigations on how Saturn and its moons (particularly Titan) respond to extreme solar wind conditions or on the transport of SEPs and GCRs in the heliosphere.",
keywords = "Saturn Magnetosphere, Solar Energetic Particles, Galactic Cosmic Rays, Radiation belts",
author = "E. Roussos and C.M. Jackman and M.F. Thomsen and W.S. Kurth and S.V. Badman and C. Paranicas and P. Kollmann and N. Krupp and R. Bu{\v c}{\'i}k and D.G. Mitchell and S.M. Krimigis and D.C. Hamilton and A. Radioti",
note = "This is the author{\textquoteright}s version of a work that was accepted for publication in Icarus. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Icarus, 300, 2017 DOI: 10.1016/j.icarus.2017.08.040",
year = "2018",
month = jan,
day = "15",
doi = "10.1016/j.icarus.2017.08.040",
language = "English",
volume = "300",
pages = "47--71",
journal = "Icarus",
issn = "0019-1035",
publisher = "ELSEVIER ACADEMIC PRESS INC",

}

RIS

TY - JOUR

T1 - Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR) as tracers of solar wind conditions near Saturn

T2 - event lists and applications

AU - Roussos, E.

AU - Jackman, C.M.

AU - Thomsen, M.F.

AU - Kurth, W.S.

AU - Badman, S.V.

AU - Paranicas, C.

AU - Kollmann, P.

AU - Krupp, N.

AU - Bučík, R.

AU - Mitchell, D.G.

AU - Krimigis, S.M.

AU - Hamilton, D.C.

AU - Radioti, A.

N1 - This is the author’s version of a work that was accepted for publication in Icarus. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Icarus, 300, 2017 DOI: 10.1016/j.icarus.2017.08.040

PY - 2018/1/15

Y1 - 2018/1/15

N2 - The lack of an upstream solar wind monitor poses a major challenge to any study that investigates the influence of the solar wind on the configuration and the dynamics of Saturn’s magnetosphere. Here we show how Cassini MIMI/LEMMS observations of Solar Energetic Particle (SEP) and Galactic Cosmic Ray (GCR) transients, that are both linked to energetic processes in the heliosphere such us Interplanetary Coronal Mass Ejections (ICMEs) and Corotating Interaction Regions (CIRs), can be used to trace enhanced solar wind conditions at Saturn’s distance. SEP protons can be easily distinguished from magnetospheric ions, particularly at the MeV energy range. Many SEPs are also accompanied by strong GCR Forbush Decreases. GCRs are detectable as a low count-rate noise signal in a large number of LEMMS channels. As SEPs and GCRs can easily penetrate into the outer and middle magnetosphere, they can be monitored continuously, even when Cassini is not situated in the solar wind. A survey of the MIMI/LEMMS dataset between 2004 and 2016 resulted in the identification of 46 SEP events. Most events last more than two weeks and have their lowest occurrence rate around the extended solar minimum between 2008 and 2010, suggesting that they are associated to ICMEs rather than CIRs, which are the main source of activity during the declining phase and the minimum of the solar cycle. We also list of 17 time periods ( >  50 days each) where GCRs show a clear solar periodicity ( ∼ 13 or 26 days). The 13-day period that derives from two CIRs per solar rotation dominates over the 26-day period in only one of the 17 cases catalogued. This interval belongs to the second half of 2008 when expansions of Saturn’s electron radiation belts were previously reported to show a similar periodicity. That observation not only links the variability of Saturn’s electron belts to solar wind processes, but also indicates that the source of the observed periodicity in GCRs may be local. In this case GCR measurements can be used to provide the phase of CIRs at Saturn. We further demonstrate the utility of our survey results by determining that: (a) Magnetospheric convection induced by solar wind disturbances associated with SEPs is a necessary driver for the formation of transient radiation belts that were observed throughout Saturn’s magnetosphere on several occasions during 2005 and on day 105 of 2012. (b) An enhanced solar wind perturbation period that is connected to an SEP of day 332/2013 was the definite source of a strong magnetospheric compression which led to open flux loading in the magnetotail. Finally, we propose how the event lists can define the basis for single case studies or statistical investigations on how Saturn and its moons (particularly Titan) respond to extreme solar wind conditions or on the transport of SEPs and GCRs in the heliosphere.

AB - The lack of an upstream solar wind monitor poses a major challenge to any study that investigates the influence of the solar wind on the configuration and the dynamics of Saturn’s magnetosphere. Here we show how Cassini MIMI/LEMMS observations of Solar Energetic Particle (SEP) and Galactic Cosmic Ray (GCR) transients, that are both linked to energetic processes in the heliosphere such us Interplanetary Coronal Mass Ejections (ICMEs) and Corotating Interaction Regions (CIRs), can be used to trace enhanced solar wind conditions at Saturn’s distance. SEP protons can be easily distinguished from magnetospheric ions, particularly at the MeV energy range. Many SEPs are also accompanied by strong GCR Forbush Decreases. GCRs are detectable as a low count-rate noise signal in a large number of LEMMS channels. As SEPs and GCRs can easily penetrate into the outer and middle magnetosphere, they can be monitored continuously, even when Cassini is not situated in the solar wind. A survey of the MIMI/LEMMS dataset between 2004 and 2016 resulted in the identification of 46 SEP events. Most events last more than two weeks and have their lowest occurrence rate around the extended solar minimum between 2008 and 2010, suggesting that they are associated to ICMEs rather than CIRs, which are the main source of activity during the declining phase and the minimum of the solar cycle. We also list of 17 time periods ( >  50 days each) where GCRs show a clear solar periodicity ( ∼ 13 or 26 days). The 13-day period that derives from two CIRs per solar rotation dominates over the 26-day period in only one of the 17 cases catalogued. This interval belongs to the second half of 2008 when expansions of Saturn’s electron radiation belts were previously reported to show a similar periodicity. That observation not only links the variability of Saturn’s electron belts to solar wind processes, but also indicates that the source of the observed periodicity in GCRs may be local. In this case GCR measurements can be used to provide the phase of CIRs at Saturn. We further demonstrate the utility of our survey results by determining that: (a) Magnetospheric convection induced by solar wind disturbances associated with SEPs is a necessary driver for the formation of transient radiation belts that were observed throughout Saturn’s magnetosphere on several occasions during 2005 and on day 105 of 2012. (b) An enhanced solar wind perturbation period that is connected to an SEP of day 332/2013 was the definite source of a strong magnetospheric compression which led to open flux loading in the magnetotail. Finally, we propose how the event lists can define the basis for single case studies or statistical investigations on how Saturn and its moons (particularly Titan) respond to extreme solar wind conditions or on the transport of SEPs and GCRs in the heliosphere.

KW - Saturn Magnetosphere

KW - Solar Energetic Particles

KW - Galactic Cosmic Rays

KW - Radiation belts

U2 - 10.1016/j.icarus.2017.08.040

DO - 10.1016/j.icarus.2017.08.040

M3 - Journal article

VL - 300

SP - 47

EP - 71

JO - Icarus

JF - Icarus

SN - 0019-1035

ER -