Cosmic Ray Modulation Observed by the Princess Sirindhorn Neutron Monitor at High Rigidity Cutoff

Mangeard, P. S.; Clem, J.; Evenson, P. A.; Pyle, R.; Mitthumsiri, W.; Ruffolo, D.; Sáiz, A.; Nutaro, Tanin

doi:10.22323/1.301.0036

Cited by 4 publications

(6 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During the second modulation period, from 2011 January to 2014 June (trimesters 13 to 26), both L and C stayed in the same range with some fluctuations, including Forbush decreases, which have not been removed in the present analysis. ( [13] showed that some but not all Forbush decreases in C are also accompanied by decreases in L.) This corresponds to a special 4-year plateau in C at Doi Inthanon, corresponding to the time when the heliospheric current sheet tilt angle 50 • , a plateau was not observed in NM at low cutoff rigidity [9]. The weak variation of L confirms that there was little systematic change in modulation conditions during this time period above the Doi Inthanon cutoff rigidity of about 17 GV.…”

Section: Pos(icrc2017)025mentioning

confidence: 97%

“…Note that NM count rates are essentially always corrected for pressure variation, and at the tropical location of Doi Inthanon, correction for water vapor is necessary when studying bare counter rates and the leader fraction [13]. [It even affects the count rate, with a peak-to-peak seasonal variation of 0.3% [9], but we do not correct the count rate for water vapor in the present work.] Those works described corrections based on the surface water vapor pressure E w at Doi Inthanon as calculated from the Global Atmospheric Data Assimilation (GDAS) database (see http://ready.arl.noaa.gov/gdas1.php).…”

Section: Normalization and Correction Of The Leader Fractionmentioning

confidence: 99%

“…Solar modulation is strongly energy-dependent [9], and a disadvantage of ground-based measurements is that the primary cosmic ray energy is not directly measured. The energy response of an NM can be controlled to some extent by its location on Earth's surface, using Earth itself as a magnetic spectrometer.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tracking cosmic-ray spectral variations with neutron monitor time-delay measurements at high cutoff rigidity during 2007-2017

Banglieng¹,

Ruffolo²,

Sáiz³

et al. 2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

Self Cite

View full text Add to dashboard Cite

We present measurements of the leader fraction of neutron monitor counts that did not follow other counts in the same counter tube from the same cosmic ray shower. We use time-delay histograms collected at the Princess Sirindhorn Neutron Monitor at Doi Inthanon, Thailand, which has the world's highest vertical cutoff rigidity for a fixed station (16.8 GV). Changes in the leader fraction are a precise indicator of cosmic ray spectral variations above the cutoff. Our data set from 2007 to 2017 spans a full cycle of solar modulation, including the all-time cosmic ray maximum of 2009 and minimum near the end of 2014, the count rate now having returned to its initial value. The electronics to collect time-delay histograms have been upgraded twice, and we have corrected for such changes to develop a long-term leader fraction dataset. We examine the spectral variation of Galactic cosmic rays above ∼17 GV resulting from solar modulation and its solar magnetic polarity dependence.

show abstract

Section: Pos(icrc2017)025mentioning

confidence: 97%

Section: Normalization and Correction Of The Leader Fractionmentioning

confidence: 99%

See 1 more Smart Citation

Tracking cosmic-ray spectral variations with neutron monitor time-delay measurements at high cutoff rigidity during 2007-2017

Banglieng¹,

Ruffolo²,

Sáiz³

et al. 2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

Self Cite

View full text Add to dashboard Cite

show abstract

“…While the term "solar modulation" most commonly refers to effects of the ∼11-year sunspot cycle and the ∼22-year solar magnetic cycle, in this category we also include other studies of temporal variations in the GCR distribution, including changes in the GCR flux and anisotropy. The temporal variations are due to solar and heliospheric effects while the GCRs propagate from outside the heliosphere to Earth, including effects of the interplanetary magnetic field (IMF), magnetic turbulence, and solar wind speed [50]. While the longer-term variations provide remote sensing of large-scale heliospheric conditions, shorter-term variations are due to more local effects, such as 27-day variations in GCRs due the solar rotation and associated changes in the solar wind passing the detector's location, as well as temporary Forbush decreases in the GCR flux due to solar storms or high speed solar wind streams.…”

Section: Solar Modulation Of Galactic Cosmic Rays (32)mentioning

confidence: 99%

“…With regard to GCR spectral variations over a solar cycle, [50] reported a distinct pattern of solar modulation at high cutoff rigidity (at Doi Inthanon, Thailand) compared with that at low cutoff (at McMurdo, Antarctica). At solar maximum conditions (or specifically, when the HCS tilt angle was high), the modulation at high cutoff rigidity tracked the magnetic field intensity.…”

Section: Spectral Variations (2)mentioning

confidence: 99%

Solar-Heliospheric Physics

Ruffolo¹

2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

Self Cite

View full text Add to dashboard Cite

This rapporteur paper summarizes the 99 presentations on solar-heliospheric physics at the 35th International Cosmic Ray Conference. These spanned a dizzying array of physical phenomena, especially time-dependent phenomena associated with solar storms, the 27-day solar rotation, the ∼11-year sunspot cycle, and the ∼22-year solar magnetic cycle. There was also work on composition-dependent effects and cosmic ray anisotropy involving transport effects. Topics included ground-and space-based instrumentation, solar energetic particles from solar storms (ranging from keV-range seed particles to GeV-range accelerated particles), interplanetary transport of energetic particles, Earth's radiation environment (including space weather and other effects of cosmic rays at Earth), the sun shadow in TeV-range Galactic cosmic rays (GCRs), and solar modulation of GCRs with the sunspot cycle and solar magnetic cycle.

show abstract

Haleakala neutron monitor redeployment and calibration with AMS data

Consolandi,

Bindi,

Corti

et al. 2023

Cosmic Ray Studies With Neutron Detectors

View full text Add to dashboard Cite

Since the 1950s, neutron monitors (NMs) have successfully measured both the long-term and the short-term variation of Galactic Cosmic Rays (GCRs). NMs are also sensitive to solar energetic particles (SEPs) and solar neutron particles (SNPs), both detected as ground level enhancements. Since SNPs are not affected by the interplanetary magnetic field, they retain direct information about the nuclear reactions happening near the SEP acceleration site. The global NM network has still a huge gap over the equatorial Pacific for measuring high energy GCRs and SNPs which are best measured at low latitudes. We plan to extend the coverage of the world wide NM network for SNP and GCR observations by redeploying the Haleakala NM station (HLEA) on Maui, in time for the upcoming solar maximum (around 2025). Since NMs can only measure the total count rate, it is not trivial to derive the actual particle flux and to compare different station responses. We plan to calibrate the HLEA with the future AMS daily proton fluxes, extended until the ISS decommission date now planned in 2031, and to perform extensive Mote Carlo simulations of the detector and surrounding environment. The initial phase of the project has already started. Status of the upcoming HLEA NM detector is reported.

show abstract

Cosmic Ray Modulation Observed by the Princess Sirindhorn Neutron Monitor at High Rigidity Cutoff

Cited by 4 publications

References 21 publications

Tracking cosmic-ray spectral variations with neutron monitor time-delay measurements at high cutoff rigidity during 2007-2017

Tracking cosmic-ray spectral variations with neutron monitor time-delay measurements at high cutoff rigidity during 2007-2017

Solar-Heliospheric Physics

Haleakala neutron monitor redeployment and calibration with AMS data

Contact Info

Product

Resources

About