Quiet-time 
                
                    
                        0.04
                        
                        –
                        
                        2
                         MeV
                        /
                        nucleon
                    
                
                $0.04\,\mbox{--}\,2\mbox{ MeV}/\mbox{nucleon}$
             Ions at 1 AU in Solar Cycles 23 and 24

Zeldovich, M. A.; Logachev, Yu. I.; Kecskeméty, K.

doi:10.1007/s11207-017-1170-8

Cited by 7 publications

(20 citation statements)

References 32 publications

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“…They are variously associated with CIRs (Chotoo et al 2000), ISEPs (Hovestadt et al 1984b,a;Desai et al 2006b), and GSEPs (Desai & Mason 2001;Mason et al 1999), depending on the phase of solar activity. In particular, prior observations suggest that CIRs are the dominant source of ST ions during solar minima (Desai et al 2006c;Dayeh et al 2009Dayeh et al , 2017Zel'dovich et al 2011Zel'dovich et al , 2018Zel'dovich et al , 2021 and both ISEP and GSEP events dominate ST sources during solar maxima (Dayeh et al 2017(Dayeh et al , 2009Desai et al 2006c). To quantify the similarity of suprathermal abundances to the known populations in Table 2, we have generated plots of quiet time X/O normalized to them Quiet Time (X/O) : Known (X/O) as a function of M/Q, averaging over each solar cycle extremum and all years from Figure 3.…”

Section: Abundances As a Function Of M/qmentioning

confidence: 98%

“…ST ions are likely associated with CIRs in solar minima (Desai et al 2006c;Dayeh et al 2009Dayeh et al , 2017Zel'dovich et al 2011Zel'dovich et al , 2018Zel'dovich et al , 2021. CIRs are formed when coronating fast solar wind streams from coronal holes overtake slow wind streams.…”

Section: Abundances During Solar Cycle Extrema M/qmentioning

confidence: 99%

“…Observations of quiet times can be identified as the lowest count levels in energetic particle detectors With such methods Dayeh et al (2017) showed that the number of quiet hours observed by ACE/ULEIS (Mason et al 1998) strongly anti-correlates with sunspot number (SSN). Multiple studies have also shown that ST abundances (normalized to oxygen, X/O) resemble solar energetic particle (SEP) events-both impulsive and gradual-in solar maxima and CIRs in solar minima (Desai et al 2006c;Dayeh et al 2009Dayeh et al , 2017Zel'dovich et al 2011Zel'dovich et al , 2018Zel'dovich et al , 2021. That the long term changes in ST ions correlate with SSN likely reflects changes in both the sources from which ST ions are drawn and the acceleration mechanisms associated with these sources (Zel'dovich et al 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Multiple studies have also shown that ST abundances (normalized to oxygen, X/O) resemble solar energetic particle (SEP) events-both impulsive and gradual-in solar maxima and CIRs in solar minima (Desai et al 2006c;Dayeh et al 2009Dayeh et al , 2017Zel'dovich et al 2011Zel'dovich et al , 2018Zel'dovich et al , 2021. That the long term changes in ST ions correlate with SSN likely reflects changes in both the sources from which ST ions are drawn and the acceleration mechanisms associated with these sources (Zel'dovich et al 2018). Whether or not the accelerating conditions are consistent across solar cycles 23 and 24 is still unresolved (Zel'dovich et al 2014;Allen et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…More recently, the name has become associated with the time profile of the energetic particles associated with the event (Reames 1999). 5 Mason et al (2016Mason et al ( , 2002 6 Allen et al (2019); Mason et al (2008); Ebert et al (2012); Fisk & Lee (1980); Richardson (2004); Desai et al (2006c); Dayeh et al (2017Dayeh et al ( , 2009Zel'dovich et al (2011Zel'dovich et al ( , 2018Zel'dovich et al ( , 2021 The reminder of this paper is organized as follows. Section 2.1 describes our quiet time selection criteria and its uncertainty metric.…”

Section: Introductionmentioning

confidence: 99%

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Solar Cycle Variation of Suprathermal Heavy Ion Composition and Spectra during Quiet Times near 1 AU

Alterman

Desai

Dayeh

et al. 2021

Preprint

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We report on the annual variation of quiet-time suprathermal ion composition and spectral properties for C-Fe using Advanced Composition Explorer (ACE)/Ultra-Low Energy Ion Spectrometer (ULEIS) over the energy range 0.3 MeV/nuc to 1.28 MeV/nuc from 1998 through 2020. This extends the work of Desai et al. (2006) and Dayeh et al. (2009Dayeh et al. ( , 2017 to cover Solar Cycle 23's rising phase through Solar Cycle 24's declining phase. With 5 additional years of data, we show that the number of quiet-time hours strongly anti-correlates with the Sunspot Number (SSN) at better than the -0.9 level. We also show (1) a clear ordering of the cross correlation between abundance (normalized to O) and SSN as a function of solar wind M/Q; (2) the slope of X/O's abundance as a function of Fe/C decreases with increasing M/Q; and (3) discuss the trend of annual spectral indicies with respect to Oxygen's spectral index as a function of solar cycle and M/Q. The contrast between our abundance and spectral index results suggests that the source from which suprathermal ions are drawn or accelerated varies with solar activity and is tied to each element's chemistry, but he acceleration mechanism that governs the spectral shape does not.

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Section: Abundances As a Function Of M/qmentioning

confidence: 98%

Section: Abundances During Solar Cycle Extrema M/qmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Solar Cycle Variation of Suprathermal Heavy Ion Composition and Spectra during Quiet Times near 1 AU

Alterman

Desai

Dayeh

et al. 2021

Preprint

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First results from the Solar Orbiter Heavy Ion Sensor

Livi¹,

Lepri²,

Raines³

et al. 2023

A&A

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Aims. Solar Orbiter launched in February 2020 with the goal of revealing the connections between the Sun’s interior, atmosphere, and the heliosphere. The Solar Orbiter Heavy Ion Sensor (HIS) is a time-of-flight ion mass spectrometer dedicated to measuring heavy ions in the solar wind. Methods. We present an overview of the first measurements of heavy ion composition from HIS, reviewing the methods used to transform the spectra obtained on board into scientific data products and examining two solar wind case studies as well as the statistical properties of the heavy ion composition observed by HIS. We also carried out a comparison with prior measurements of heavy ions at L1. Results. The HIS data set provides the first mass- and charge-resolved heavy ion measurements in the inner heliosphere. Conclusions. These high temporal resolution data have the potential to transform our understanding of the connections between the solar wind and its origin at the Sun, as well as the interaction between the solar wind and the environment around planets, comets, and in the interstellar medium.

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Suprathermal ions from coronal holes at 1 au in solar cycles 23 and 24: dependence of ion abundances on solar wind speed

Zeldovich

Kecskeméty

Logachev

2021

Monthly Notices of the Royal Astronomical Society

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The relative abundances of thermal and suprathermal C, O, and Fe ions are analyzed and compared in solar wind streams from near-equatorial coronal holes during quiet periods of nearly two solar cycle minima. Ion fluxes with energies of ∼0.04–2 MeV/nucleon are studied using data from the ULEIS instrument aboard the ACE spacecraft together with thermal ions in the fast and slow (Maxwellian) solar wind using data from the SWICS instrument aboard ACE. The analysis was carried out for quiescent periods in 2006–2012 and 2015–17 when solar wind flows from near-equatorial coronal holes (CHs) were detected at 1 AU. Near the minimum of SC23, although they displayed large variability, the C/O and Fe/O ratios of suprathermal ions were, on average, near the corresponding relative abundances of the solar wind. During the decreasing solar activity phase of SC24 suprathermal Fe/O ratios matched those of solar wind ions from CHs. In both cycles the thermal and suprathermal Fe/O ratios exhibited a similar character of dependence on maximum solar wind speed. Our results suggest that the sources of suprathermal ions from CHs in low solar activity periods are accelerated solar wind thermal ions. The thermal and suprathermal Fe/O ratios were found to be higher in 2015–17 in comparison to the ratios measured in 2006–2010. This difference can be attributed to that the second quiet period was selected at times when solar activity has not reached its minimum of SC24 yet.

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Quiet-time 0.04 – 2 MeV / nucleon $0.04\,\mbox{--}\,2\mbox{ MeV}/\mbox{nucleon}$ Ions at 1 AU in Solar Cycles 23 and 24

Cited by 7 publications

References 32 publications

Solar Cycle Variation of Suprathermal Heavy Ion Composition and Spectra during Quiet Times near 1 AU

Solar Cycle Variation of Suprathermal Heavy Ion Composition and Spectra during Quiet Times near 1 AU

First results from the Solar Orbiter Heavy Ion Sensor

Suprathermal ions from coronal holes at 1 au in solar cycles 23 and 24: dependence of ion abundances on solar wind speed

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