Variations in cutoff latitude during selected solar energetic proton events

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Variations in cutoff latitude during selected solar energetic proton events. / Birch, M. J.; Hargreaves, J. K.; Senior, Andrew et al.
In: Journal of Geophysical Research, Vol. 110, No. A7, 07.2005, p. A07221.

Research output: Contribution to Journal/Magazine › Journal article › peer-review

Harvard

Birch, MJ, Hargreaves, JK, Senior, A & Bromage, BJI 2005, 'Variations in cutoff latitude during selected solar energetic proton events', Journal of Geophysical Research, vol. 110, no. A7, pp. A07221. https://doi.org/10.1029/2004JA010833

APA

Birch, M. J., Hargreaves, J. K., Senior, A., & Bromage, B. J. I. (2005). Variations in cutoff latitude during selected solar energetic proton events. Journal of Geophysical Research, 110(A7), A07221. https://doi.org/10.1029/2004JA010833

Vancouver

Birch MJ, Hargreaves JK, Senior A, Bromage BJI. Variations in cutoff latitude during selected solar energetic proton events. Journal of Geophysical Research. 2005 Jul;110(A7):A07221. doi: 10.1029/2004JA010833

Author

Birch, M. J. ; Hargreaves, J. K. ; Senior, Andrew et al. / Variations in cutoff latitude during selected solar energetic proton events. In: Journal of Geophysical Research. 2005 ; Vol. 110, No. A7. pp. A07221.

Bibtex

@article{78c2ca9d61ea46469e720a0c937ec827,

title = "Variations in cutoff latitude during selected solar energetic proton events",

abstract = "Proton count rate measurements were obtained from the polar orbiting environmental satellites POES15 and POES16 during three solar proton events in 2001. From these data the invariant latitude of the cutoff in proton flux was determined at four local times. The satellites sample the edge of the northern polar cap at approximately 0300, 0830, 1230, and 1800 hours local time, covering the early morning, late morning, noon, and evening. During the event of 2 April the cutoff latitude for 35–70 MeV protons was almost constant, showing no more than 1.5° variation with local time. CME impacts occurred during the 24 September and 4 November events, the effects of which were to reduce the cutoff latitudes by between 5° and 8°. The equatorward displacement of the cutoff latitude was found to be strongly correlated with the magnetic storm indices (D st and SYM-H). Cutoff latitude prediction formulae are defined. Simulations using the Tsyganenko (2002) model of the magnetosphere are consistent with observations to within 2σ during quiet conditions and weak disturbances.",

keywords = "solar, magnetosphere, modelling, POES, satellite, cutoff DCS-publications-id, art-704, DCS-publications-credits, iono, DCS-publications-personnel-id, 6, 51",

author = "Birch, {M. J.} and Hargreaves, {J. K.} and Andrew Senior and Bromage, {B. J. I.}",

note = "Copyright (2005) American Geophysical Union.",

year = "2005",

month = jul,

doi = "10.1029/2004JA010833",

language = "English",

volume = "110",

pages = "A07221",

journal = "Journal of Geophysical Research",

issn = "0148-0227",

publisher = "American Geophysical Union",

number = "A7",

}

RIS

TY - JOUR

T1 - Variations in cutoff latitude during selected solar energetic proton events

AU - Birch, M. J.

AU - Hargreaves, J. K.

AU - Senior, Andrew

AU - Bromage, B. J. I.

N1 - Copyright (2005) American Geophysical Union.

PY - 2005/7

Y1 - 2005/7

N2 - Proton count rate measurements were obtained from the polar orbiting environmental satellites POES15 and POES16 during three solar proton events in 2001. From these data the invariant latitude of the cutoff in proton flux was determined at four local times. The satellites sample the edge of the northern polar cap at approximately 0300, 0830, 1230, and 1800 hours local time, covering the early morning, late morning, noon, and evening. During the event of 2 April the cutoff latitude for 35–70 MeV protons was almost constant, showing no more than 1.5° variation with local time. CME impacts occurred during the 24 September and 4 November events, the effects of which were to reduce the cutoff latitudes by between 5° and 8°. The equatorward displacement of the cutoff latitude was found to be strongly correlated with the magnetic storm indices (D st and SYM-H). Cutoff latitude prediction formulae are defined. Simulations using the Tsyganenko (2002) model of the magnetosphere are consistent with observations to within 2σ during quiet conditions and weak disturbances.

AB - Proton count rate measurements were obtained from the polar orbiting environmental satellites POES15 and POES16 during three solar proton events in 2001. From these data the invariant latitude of the cutoff in proton flux was determined at four local times. The satellites sample the edge of the northern polar cap at approximately 0300, 0830, 1230, and 1800 hours local time, covering the early morning, late morning, noon, and evening. During the event of 2 April the cutoff latitude for 35–70 MeV protons was almost constant, showing no more than 1.5° variation with local time. CME impacts occurred during the 24 September and 4 November events, the effects of which were to reduce the cutoff latitudes by between 5° and 8°. The equatorward displacement of the cutoff latitude was found to be strongly correlated with the magnetic storm indices (D st and SYM-H). Cutoff latitude prediction formulae are defined. Simulations using the Tsyganenko (2002) model of the magnetosphere are consistent with observations to within 2σ during quiet conditions and weak disturbances.

KW - solar

KW - magnetosphere

KW - modelling

KW - POES

KW - satellite

KW - cutoff DCS-publications-id

KW - art-704

KW - DCS-publications-credits

KW - iono

KW - DCS-publications-personnel-id

KW - 6

KW - 51

U2 - 10.1029/2004JA010833

DO - 10.1029/2004JA010833

M3 - Journal article

VL - 110

SP - A07221

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - A7

ER -

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