Rotating solar coronal holes and periodic modulation of the upper atmosphere

Lei, Jiuhou; Thayer, J. P.; Forbes, Jeffrey M.; Sutton, E. K.; Nerem, R. S.

doi:10.1029/2008gl033875

Cited by 132 publications

(191 citation statements)

References 21 publications

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“…During the solar maximum, CHs are distributed at all latitudes, while at solar minimum, CHs mainly occur near the polar regions (Madjarska & Wiegelmann 2009). In addition to sunspot activity and magnetic activity phenomena that strongly influence the Earth's climate (Hiremath 2009 and references therein), there is increasing evidence that, on short timescales, occurrences of solar CHs trigger responses in Earth's upper atmosphere and magnetosphere (Soon et al 2000;Lei et al 2008;Shugai et al 2009;Sojka et al 2009;Choi et al 2009;Ram et al 2010;Verbanac et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Rotation Rates of Coronal Holes and Their Probable Anchoring Depths

Hiremath

Hegde

2013

ApJ

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From 2001From -2008, we use full-disk, SOHO/EIT 195 Å calibrated images to determine latitudinal and day-to-day variations of the rotation rates of coronal holes (CHs). We estimate the weighted average of heliographic coordinates such as latitude and longitude from the central meridian on the observed solar disk. For different latitude zones between 40• north and 40• south, we compute rotation rates and find that, irrespective of their area, the number of days observed on the solar disk, and their latitudes, CHs rotate rigidly. Combined for all the latitude zones, we also find that CHs rotate rigidly during their evolution history. In addition, for all latitude zones, CHs follow a rigid body rotation law during their first appearance. Interestingly, the average first rotation rate (∼438 nHz) of CHs, computed from their first appearance on the solar disk, matches the rotation rate of the solar interior only below the tachocline.

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Section: Introductionmentioning

confidence: 99%

Rotation Rates of Coronal Holes and Their Probable Anchoring Depths

Hiremath

Hegde

2013

ApJ

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“…The strong 9-day periods in 2005 and 2008 and the 7-day periods in 2006 were also seen in K p , the neutral thermosphere density Lei et al, 2008aLei et al, , 2008bLei et al, , 2011, total electron content TEC (Lei et al, 2008c), neutral thermospheric polar winds (Lei et al, 2008c), and infrared NO and CO 2 cooling (Mlynczak et al, 2008(Mlynczak et al, , 2010, and were absent or weak in the TIMED/SEE short wavelength radiation flux and 10.7 cm solar flux.…”

Section: Discussionmentioning

confidence: 87%

“…The 9-day periodicity in 2005 and 2008 seen in the solar wind, the electron auroral power, and the radiation belt electron flux at 6.6 R E (for 2008), was also seen in the neutral density at 400 km (Lei et al, 2008a(Lei et al, , 2008b(Lei et al, , 2011, in the total electron content (TEC) (Lei et al, 2008c), in the polar thermospheric neutral winds (Lei et al, 2008c), and in the power radiated through infrared cooling by CO 2 and NO between 100 and 200 km (Mlynczak et al, 2008(Mlynczak et al, , 2010. The 2006 7-d peak was observed again in these same thermospheric quantities by Lei et al (2008bLei et al ( , 2008c, Thayer et al (2008), and Mlynczak et al (2010).…”

Section: Introductionmentioning

confidence: 77%

Solar Rotational Periodicities and the Semiannual Variation in the Solar Wind, Radiation Belt, and Aurora

Emery

Richardson

Evans³

et al. 2011

Sol Phys

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The behavior of a number of solar wind, radiation belt, auroral and geomagnetic parameters is examined during the recent extended solar minimum and previous solar cycles, covering the period from January 1972 to July 2010. This period includes most of the solar minimum between Cycles 23 and 24, which was more extended than recent solar minima, with historically low values of most of these parameters in 2009. Solar rotational periodicities from 5 to 27 days were found from daily averages over 81 days for the parameters. There were very strong 9-day periodicities in many variables in 2005 -2008, triggered by recurring corotating high-speed streams (HSS). All rotational amplitudes were relatively large in the descending and early minimum phases of the solar cycle, when HSS are the predominant solar wind structures. There were minima in the amplitudes of all solar rotational periodicities near the end of each solar minimum, as well as at the start of the reversal of the solar magnetic field polarity at solar maximum (∼ 1980, ∼ 1990, and ∼ 2001) when the occurrence frequency of HSS is relatively low. Semiannual equinoctial periodicities, which were relatively strong in the 1995 -1997 solar minimum, were found to be primarily the result of the changing amplitudes of the 13.5-and 27-day periodicities, where 13.5-day amplitudes were better correlated with heliospheric daily observations and 27-day amplitudes correlated better with Earth-based daily observations. The equinoctial rotational amplitudes of the Earth-based parameters were probably enhanced by a combination of the Russell-McPherron effect and a reduction in the solar wind-magnetosphere coupling efficiency during solstices. The rotational amplitudes were cross-correlated with each other, where the 27-day amplitudes showed some of the weakest cross-correlations. The rotational amplitudes of the > 2 MeV radiation belt electron number fluxes were progressively weaker from 27-to 5-day periods, showing that processes in the magnetosphere act as a low-pass filter between the solar wind and the radiation belt. The A p /K p magnetic currents observed at subauroral latitudes are sensitive to proton auroral precipitation, especially for 9-day and shorter periods, while the A p /K p currents are governed by electron auroral precipitation for 13.5-and 27-day periodicities.

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“…They pointed out that the total thermosphere density changes and satellite orbit decays for entire periods of CIR-storms were greater than those for CMEstorms because CME-storms were shorter than CIR storms, although CME-storms were stronger than CIR-storms on average. Since the CIRs/solar wind high-speed streams occur frequently and periodically, details of the thermosphere density variations have been investigated by, e.g., , Lei et al (2008aLei et al ( , b, 2011, Sojka et al (2009), and Gardner et al (2012) during the declining phase and near the minimum of the solar cycle. However, since CME events are less frequent than CIRs without periodic occurrence, details of responses of the ionosphere and thermosphere to the CME-induced geomagnetic activity are relatively unknown.…”

Section: Introductionmentioning

confidence: 99%

Extreme ion heating in the dayside ionosphere in response to the arrival of a coronal mass ejection on 12 March 2012

et al. 2014

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Abstract. Simultaneous measurements of the polar ionosphere with the European Incoherent Scatter (EISCAT) ultra high frequency (UHF) radar at Tromsø and the EISCAT Svalbard radar (ESR) at Longyearbyen were made during 07:00-12:00 UT on 12 March 2012. During the period, the Advanced Composition Explorer (ACE) spacecraft observed changes in the solar wind which were due to the arrival of coronal mass ejection (CME) effects associated with the 10 March M8.4 X-ray event. The solar wind showed two-step variations which caused strong ionospheric heating. First, the arrival of shock structures in the solar wind with enhancements of density and velocity, and a negative interplanetary magnetic field (IMF)-B z component caused strong ionospheric heating around Longyearbyen; the ion temperature at about 300 km increased from about 1100 to 3400 K over Longyearbyen while that over Tromsø increased from about 1050 to 1200 K. After the passage of the shock structures, the IMF-B z component showed positive values and the solar wind speed and density also decreased. The second strong ionospheric heating occurred after the IMF-B z component showed negative values again; the negative values lasted for more than 1.5 h. This solar wind variation caused stronger heating of the ionosphere in the lower latitudes than higher latitudes, suggesting expansion of the auroral oval/heating region to the lower latitude region. This study shows an example of the CME-induced dayside ionospheric heating: a short-duration and very large rise in the ion temperature which was closely related to the polar cap size and polar cap potential variations as a result of interaction between the solar wind and the magnetosphere.

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Rotating solar coronal holes and periodic modulation of the upper atmosphere

Cited by 132 publications

References 21 publications

Rotation Rates of Coronal Holes and Their Probable Anchoring Depths

Rotation Rates of Coronal Holes and Their Probable Anchoring Depths

Solar Rotational Periodicities and the Semiannual Variation in the Solar Wind, Radiation Belt, and Aurora

Extreme ion heating in the dayside ionosphere in response to the arrival of a coronal mass ejection on 12 March 2012

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