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Hakamada, K.; Kojima, M.; Tokumaru, M.; Ohmi, Tetsuo; Yokobe, A.; Fujiki, K.

doi:10.1023/a:1015511805863

Cited by 17 publications

(9 citation statements)

References 18 publications

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“…Hakamada and Kojima (1999) reported that the SWS is well correlated negatively with the RBR during CR 1909 in the minimum phase of the solar activity cycle. Hakamada et al (2002) also reported similar results for CR 1830 and CR 1901. In their paper, the correlation analysis was performed in the restricted time period in the solar maximum and the minimum phases.…”

Section: Introductionsupporting

confidence: 65%

“…In a previous paper (Hakamada et al, 2002) we found the following empirical equation by using the SWS and the RBR of two Carrington rotations, CR 1830 and CR 1901, where CR 1830 is around the maximum phase of solar activity cycle and CR 1901 is around the minimum phase;…”

Section: Resultsmentioning

confidence: 93%

“…The discrepancy between these two empirical equations was also discussed in the previous paper (Hakamada et al, 2002). For Equation (2), we used all data of two Carrington rotations.…”

Section: Resultsmentioning

confidence: 95%

“…This relation has been studied extensively by Wang et al (1997, and references therein). Since then, relations between the SWS and the CMF have been studied by many scientists (Hakamada, 1998;Hakamada and Kojima, 1999;Hakamada et al, 2002). Hakamada and Kojima (1999) reported that the SWS is well correlated negatively with the RBR during CR 1909 in the minimum phase of the solar activity cycle.…”

Section: Introductionmentioning

confidence: 99%

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Correlation between Expansion Rate of the Coronal Magnetic Field and Solar Wind Speed in a Solar Activity Cycle

et al. 2005

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Thirteen synoptic maps of expansion rate of the coronal magnetic field (CMF; RBR) calculated by the so-called 'potential model' are constructed for 13 Carrington rotations from the maximum phase of solar activity cycle 22 through the maximum phase of cycle 23. Similar 13 synoptic maps of solar wind speed (SWS) estimated by interplanetary scintillation observations are constructed for the same 13 Carrington rotations as the ones for the RBR. The correlation diagrams between the RBR and the SWS are plotted with the data of these 13 synoptic maps. It is found that the correlation is negative and high in this time period. It is further found that the linear correlation is improved if the data are classified into two groups by the magnitude of radial component of photospheric magnetic field, |B pho r |; group 1, 0.0 G |B pho r | < 17.8 G and group 2, 17.8 G |B pho r |. There exists a strong negative correlation between the RBR and the SWS for the group 1 in contrast with a weak negative correlation for the group 2. Group 1 has a double peak in the density distribution of data points in the correlation diagram; a sharp peak for high-speed solar wind and a low peak for low-speed solar wind. These two peaks are located just on the axis of maximum variance of data points in the correlation diagram. This result suggests that the solar wind consists of two major components and both the highspeed and the low-speed winds emanating from weak photospheric magnetic regions are accelerated by the same mechanism in the course of solar activity cycle. It is also pointed out that the SWS can be estimated by the RBR of group 1 with an empirical formula obtained in this paper during the entire solar activity cycle.

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Section: Introductionsupporting

confidence: 65%

Section: Resultsmentioning

confidence: 93%

“…The discrepancy between these two empirical equations was also discussed in the previous paper (Hakamada et al, 2002). For Equation (2), we used all data of two Carrington rotations.…”

Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Correlation between Expansion Rate of the Coronal Magnetic Field and Solar Wind Speed in a Solar Activity Cycle

et al. 2005

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“…The solar wind could be accelerated and heated by high-frequency magnetosonic waves (Joarder 2002), damping of low-frequency Alfvén waves (Lou 2002), by MHD turbulence (Spangler et al 2002), as well as by shocks at the corotating interaction regions (CIR) between fast and slow solar wind zones (Mann et al 2002). Relationships between solar wind speeds and the expansion rate for the coronal magnetic field were also measured with interplanetary scintillation observations (Hakamada et al 2002;Spangler et al 2002;Lotova et al 2002). Oddly, extremely high ion kinetic temperatures (exceeding 10 8 K) were reported at the North Pole in 2001, nearly simultaneously with the polarity change of the Sun's magnetic field (Miralles et al 2001).…”

Section: Solar Windmentioning

confidence: 99%

Astrophysics in 2002

Trimble

Aschwanden

2003

PUBL ASTRON SOC PAC

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ABSTRACT. This has been the Year of the Baryon. Some low temperature ones were seen at high redshift, some high temperature ones were seen at low redshift, and some cooling ones were (probably) reheated. Astronomers saw the back of the Sun (which is also made of baryons), a possible solution to the problem of ejection of material by Type II supernovae (in which neutrinos push out baryons), the production of R Coronae Borealis stars (previously-owned baryons), and perhaps found the missing satellite galaxies (whose failing is that they have no baryons). A few questions were left unanswered for next year, and an attempt is made to discuss these as well.

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North‐south asymmetry in global distribution of the solar wind speed during 1985–2013

2015

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Interplanetary scintillation (IPS) observations made between 1985 and 2013 are used to investigate the north-south (N-S) asymmetry in global distribution of the solar wind speed. The IPS observations clearly demonstrate that the global distribution of the solar wind speed systematically changes with the solar activity. This change is found to closely correlate with that in polar magnetic fields of the Sun, while fast wind data at solar minima systematically deviate from this correlation. The IPS observations show that notable N-S asymmetry of polar solar winds occurs at the solar maxima, and small but significant N-S asymmetry exists at the solar minima. The observed asymmetry at the solar maxima is consistent with the time lag in the reversal of polar magnetic fields between north and south hemispheres. We also find that significant N-S asymmetry of the polar fast wind lasts for the period between Cycles 23 and 24 solar maxima, starting from predominance of the fast wind over the north pole and ending with that over the south pole. The N-S asymmetry revealed from IPS observations is found to be generally consistent with Ulysses observations. We compare IPS observations with magnetic field data of the Sun and find that the ratio of the quadrupole to dipole coefficients exhibits a similar time variation to that of the N-S asymmetry revealed from IPS observations. This suggests that higher-order multipole moments play an important role in determining the N-S asymmetry of the solar wind when the dipole moment weakens.

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Cited by 17 publications

References 18 publications

Correlation between Expansion Rate of the Coronal Magnetic Field and Solar Wind Speed in a Solar Activity Cycle

Correlation between Expansion Rate of the Coronal Magnetic Field and Solar Wind Speed in a Solar Activity Cycle

Astrophysics in 2002

North‐south asymmetry in global distribution of the solar wind speed during 1985–2013

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