近地太阳风参数与源区性质的相关性研究
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摘要
近地空间环境变化主要受到太阳活动的影响,其中太阳风是太阳施加影响于近地空间的一个重要媒介。然而,在讨论空间天气学效应时,绝大多数研究往往集中在日冕物质抛射(CME)和耀斑等太阳爆发现象的作用,而对源自冕洞的太阳风高速流及其伴随的共转相互作用区(CIR)的影响讨论较少。然而,事实上至少在太阳活动周的下降和极小期,影响地磁活动的主要因素便是高速流及CIR。因此,研究地球附近的太阳风参数与其太阳源区的关系,并最终实现对lAU处太阳风参数的预测,不仅是太阳物理研究中的一个重要基础课题,也是空间天气学研究的主要应用之一。本文将利用不同的磁场外推模型得到的日冕磁场结构来推测近地太阳风在低日冕高度的源区位置,并利用太阳日冕紫外波段的全日面观测数据和磁场外推数据得到源区位置的各物理参数,进而研究近地太阳风参数尤其是速度和太阳风源区各物理参数的关系。主要的结论如下：
1)通过比较我们发现,PFSS (Potential Field Source Surface)模型和CSSS (Current Sheet Source Surface)模型虽然都对太阳日冕磁场做了这样或者那样的简单假设,但是利用PFSS模型和CSSS模型计算的日冕磁力线追踪得到的太阳风源区与EIT极紫外图像上的冕洞区域比较吻合。并且,在多数情况下,两模型得到的源表面上同一根开放磁力线在太阳光球层源区位置有较好的一致性。上述结果表明,其外推的太阳日冕磁场结构可以运用到本文的研究。
2)所有冕洞对应的光球层磁场净通量均不为零,面积小的冕洞对应的光球层磁场通量不均衡性较高(即某一极性磁通量占总磁通量比例较大),足跟磁场强度较大,冕洞区域平均亮度较高；近地太阳风速度和冕洞的面积正相关；同时近地太阳风速度还和冕洞的亮度有关,冕洞亮度和近地太阳风速度成负相关；近地太阳风速度和整个冕洞的膨胀因子也成负相关。
3)我们定义一个表征太阳风源区内日冕辐射亮度的参数ISR(ISR=∑(1／b~(1/2))／N,b为EIT的辐射亮度,N为像元数),发现该参数与相应的近地太阳风速度V在非太阳活动高年存在较好相关性。在不同的太阳活动阶段,这个参数的倒数1／ISR和同一区域日冕磁场径向分量强度之间一直存在比较好的相关性,这说明太阳风的源区等离子体电子密度n和开放磁场的径向磁场B呈正相关。
The space environment near the Earth is mainly influenced by the solar activities. For example, the solar wind is an important medium through which the Sun can impact the near-Earth space environment. However, when the geoeffectiveness of the solar acitivities were discussed, most studies focused on the effects caused by the solar dramtic eruptions such as coronal mass ejections (CMEs) and flares, while those driven by the high-speed streams (HSSs) with their source region in the coronal hole and associated corotating interaction regions (CIRs) are seldom discussed. Nervertheless. at least during the descending phases and the minima of solar cycles, the HSSs and CIRs are the main sources and drivers of catastropic events in the Earth's magnetosphere. Therefore, it is important to study the relationship between solar wind parameters observed at 1AU and their source region properties, which may be further used to predict the solar wind parameters at 1 AU. In this thesis, we will use the PFSS and CSSS models respectively to extrapolate the coronal magnetic fields and identify the relevant source regions of selected solar wind streams. Then we deduce the parameters such as bightness and magnetic fields in the source regions using EIT full disk images and the extrapolated magnetic field data. Finally, we analyse the correlation of solar wind speeds at 1AU and relevant parameters in the source regions. The main findings can be summarized as follows:
1) Although the PFSS (Potential Field Source Surface) model and CSSS (Current Sheet Source Surface) model are used to calculate the coronal magnetic fields with a series of assumptions, the source regions of the high-speed streams identified by these extrapolated magnetic fields generally coincide with the coronal hole regions observed on the disk by EIT at the 284 passband. And in most cases, an open field line on the source surface of the two models can be traced back to the same location (footpoint) on the solar disk. The result demonstrates that the extrapolated coronal magnetic fields can be used for our further study.
2) The averaged net flux of the photospheric magnetic fields in all selected coronal holes is non-zero, i.e., one polarity of magnetic fields dominates there. The ratio of the flux of the dominated polarity fields to the total flux of the magnetic fields is larger in the coronal holes with smaller areas. We also found that the coronal hole regions seen in EIT images become brighter with increasing magnetic field strength. We confirm previous results that the solar wind velocity increases with increasing area of the cornal holes and with decreasing areal expansion factor of the high-speed stream tube. Moreover, our analysis shows a close correlation between the solar wind velocity and the brightness of the coronal holes seen in EIT images. The correlation coefficient is negative, indicating that a darker coronal hole has a faster solar wind stream at 1 AU.
3) We define a parameter that may represent the variation of the coronal brightness, namely, ISR=∑(1/(?))/N. where b is the brightness at every pixel and N is the number of pixels. We found that the parameter ISR deduced from the source regions of the solar wind has a good correlation with the corresponding solar wind velocity at different phases of solar cycles except for the solar maxima. Meanwhile, the parameter 1/ISR shows a good correlation with radial magnetic field strength over the whole solar cycle. Because 1/ISR is somehow related to the electron density of the source regions, this may imply that the average electron density is approximately proportional to the magnetic field strength at solar wind source regions.
1)通过比较我们发现,PFSS (Potential Field Source Surface)模型和CSSS (Current Sheet Source Surface)模型虽然都对太阳日冕磁场做了这样或者那样的简单假设,但是利用PFSS模型和CSSS模型计算的日冕磁力线追踪得到的太阳风源区与EIT极紫外图像上的冕洞区域比较吻合。并且,在多数情况下,两模型得到的源表面上同一根开放磁力线在太阳光球层源区位置有较好的一致性。上述结果表明,其外推的太阳日冕磁场结构可以运用到本文的研究。
2)所有冕洞对应的光球层磁场净通量均不为零,面积小的冕洞对应的光球层磁场通量不均衡性较高(即某一极性磁通量占总磁通量比例较大),足跟磁场强度较大,冕洞区域平均亮度较高；近地太阳风速度和冕洞的面积正相关；同时近地太阳风速度还和冕洞的亮度有关,冕洞亮度和近地太阳风速度成负相关；近地太阳风速度和整个冕洞的膨胀因子也成负相关。
3)我们定义一个表征太阳风源区内日冕辐射亮度的参数ISR(ISR=∑(1／b~(1/2))／N,b为EIT的辐射亮度,N为像元数),发现该参数与相应的近地太阳风速度V在非太阳活动高年存在较好相关性。在不同的太阳活动阶段,这个参数的倒数1／ISR和同一区域日冕磁场径向分量强度之间一直存在比较好的相关性,这说明太阳风的源区等离子体电子密度n和开放磁场的径向磁场B呈正相关。
The space environment near the Earth is mainly influenced by the solar activities. For example, the solar wind is an important medium through which the Sun can impact the near-Earth space environment. However, when the geoeffectiveness of the solar acitivities were discussed, most studies focused on the effects caused by the solar dramtic eruptions such as coronal mass ejections (CMEs) and flares, while those driven by the high-speed streams (HSSs) with their source region in the coronal hole and associated corotating interaction regions (CIRs) are seldom discussed. Nervertheless. at least during the descending phases and the minima of solar cycles, the HSSs and CIRs are the main sources and drivers of catastropic events in the Earth's magnetosphere. Therefore, it is important to study the relationship between solar wind parameters observed at 1AU and their source region properties, which may be further used to predict the solar wind parameters at 1 AU. In this thesis, we will use the PFSS and CSSS models respectively to extrapolate the coronal magnetic fields and identify the relevant source regions of selected solar wind streams. Then we deduce the parameters such as bightness and magnetic fields in the source regions using EIT full disk images and the extrapolated magnetic field data. Finally, we analyse the correlation of solar wind speeds at 1AU and relevant parameters in the source regions. The main findings can be summarized as follows:
1) Although the PFSS (Potential Field Source Surface) model and CSSS (Current Sheet Source Surface) model are used to calculate the coronal magnetic fields with a series of assumptions, the source regions of the high-speed streams identified by these extrapolated magnetic fields generally coincide with the coronal hole regions observed on the disk by EIT at the 284 passband. And in most cases, an open field line on the source surface of the two models can be traced back to the same location (footpoint) on the solar disk. The result demonstrates that the extrapolated coronal magnetic fields can be used for our further study.
2) The averaged net flux of the photospheric magnetic fields in all selected coronal holes is non-zero, i.e., one polarity of magnetic fields dominates there. The ratio of the flux of the dominated polarity fields to the total flux of the magnetic fields is larger in the coronal holes with smaller areas. We also found that the coronal hole regions seen in EIT images become brighter with increasing magnetic field strength. We confirm previous results that the solar wind velocity increases with increasing area of the cornal holes and with decreasing areal expansion factor of the high-speed stream tube. Moreover, our analysis shows a close correlation between the solar wind velocity and the brightness of the coronal holes seen in EIT images. The correlation coefficient is negative, indicating that a darker coronal hole has a faster solar wind stream at 1 AU.
3) We define a parameter that may represent the variation of the coronal brightness, namely, ISR=∑(1/(?))/N. where b is the brightness at every pixel and N is the number of pixels. We found that the parameter ISR deduced from the source regions of the solar wind has a good correlation with the corresponding solar wind velocity at different phases of solar cycles except for the solar maxima. Meanwhile, the parameter 1/ISR shows a good correlation with radial magnetic field strength over the whole solar cycle. Because 1/ISR is somehow related to the electron density of the source regions, this may imply that the average electron density is approximately proportional to the magnetic field strength at solar wind source regions.
引文
Altschuler, Martin D.; Newkirk. Gordon, Magnetic Fields and the Structure of the Solar Corona. I:Methods of Calculating Coronal Fields, Solar Phy sics,9,131-149,1969.
Arge, Charles N.; Odstrcil, Dusan; Pizzo, Victor J.; Mayer, Leslie R., Improved Method for Specifying Solar Wind Speed Near the Sun. SOLAR WIND TEN: Proceedings of the Tenth International Solar Wind Conference. AIP Conference Proceedings,679,190-193,2003.
Biermann, L., Kometenschweife und solare Korpuskularstrahlung, Zeitschrift fur Astrophysik,29,274,1951.
Chertok, I. M.; Obridko, E. I.; Mogilevsky, V. N.; Shilova, N. S.; Hudson, H. S., Solar Disappearing Filament Inside a Coronal Hole, The Astrophysical Journal,567,1225-1233,2002.
Cranmer, S. R., Why is the Fast Solar Wind Fast and the Slow Solar Wind Slow? (Invited) A Survey of Geometrical Models, Proceedings of the Solar Wind 11/SOHO 16, "Connecting Sun and Heliosphere" Conference,159,2005.
Cranmer, Steven R., Coronal Holes, Living Reviews in Solar Physics, vol.6, no. 3,2009.
DeForest, C. E.; Lamy, P. L.; Llebaria, A., Solar Polar Plume Lifetime and Coronal Hole Expansion:Determination from Long-Term Observations, The Astrophysical Journal,560,490-498,2001.
E.Marsch,Solar wind models from the sun to 1 AU:constraints by in situ and remote sensing measurements,Space Science Reviews,87,1-24,1999.
Fisher, Richard; Guhathakurta, Madhulika, Physical Properties of Polar Coronal Rays and Holes as Observed with the SPARTAN 201-01 Coronagraph, Astrophysical Journal Letters,447,L139,1995.
Gonzalez, W. D., B. T. Tsurutani, and A. L. Clua de Gonzalez,Interplanetary origin of geomagnetic storms, Space Sci. Rev.,88,529-562.,1999.
Habbal, Shadia Rifai; Woo, Richard, Connecting the Sun and the Solar Wind: Comparison of the Latitudinal Profiles of Coronal and Ulysses Measurements of the Fast Wind, The Astrophysical Journal,549,L253-L256,2001.
Hansteen, Viggo H.; Leer, Egil, Coronal heating, densities, and temperatures and solar wind acceleration. Journal of Geophysical Research,100,21577-21594,1995.
Hundhausen, A. J., An interplanetary view of coronal holes, Coronal holes and high speed wind streams,225-329,1977.
Kivelson,M.G.,Russell,C.T.,Introduction to Space Physics,91,1995.
Krieger, A. S.; Timothy, A. F.; Roelof, E. C., A Coronal Hole and Its Identification as the Source of a High Velocity Solar Wind Stream,Solar Physics,29,505-525,1973.
Luo, Bingxian; Zhong, Qiuzhen; Liu, Siqing; Gong, Jiancun, A New Forecasting Index for Solar Wind Velocity Based on EIT 284 (?) Observations, Solar Physics,250,159-170,2008.
Moses, D.; Clette, F.; Delaboudiniere, J.-P.; Artzner, G. E.; Bougnet, M.; Brunaud, J.; Carabetian, C.; Gabriel, A. H.; Hochedez, J. F.; Millier, F.; Song, X. Y.; Au, B.; Dere, K. P.; Howard, R. A.; Kreplin, R.; Michels, D. J.; Defise, J. M.; Jamar, C.; Rochus, P.; Chauvineau, J. P.; Marioge, J. P.; Catura, R. C.; Lemen, J. R.; Shing, L.; Stern, R. A.; Gurman, J. B.; Neupert, W. M.; Newmark, J.; Thompson, B.; Maucherat, A.; Portier-Fozzani, F.; Berghmans, D.; Cugnon, P.; van Dessel, E. L.; Gabryl, J. R., EIT Observations of the Extreme Ultraviolet Sun, Solar Physics,175,571-599,1997.
Munro, R. H.; Jackson, B. V., Physical properties of a polar coronal hole from 2 to 5 solar radii, Astrophysical Journal,213,874,875,877-886,1977.
Neugebauer,Marcia;Snyder,Conway,W.,SolarPlasma Experiment,Science,138,1095-1097,1962. Noci, Giancarlo, Energy Budget in Coronal Holes, Solar Physics,28,403-407,1973.
Parker,E.N., Dynamics of the Interplanetary Gas and Magnetic Fields, Astrophysical Journal,128,664,1958.
Riley, Pete; Linker, J. A.; Mikic, Z.; Lionello, R.; Ledvina, S. A.; Luhmann, J. G., A Comparison between Global Solar Magnetohydrodynamic and Potential Field Source Surface Model Results, The Astrophysical Journal,653,1510-1516,2006.
Robbins, S.; Henney, C. J.; Harvey, J. W., Solar Wind Forecasting with Coronal Holes, Solar Physics,233,265-276,2006.
Schatten, Kenneth H.; Wilcox, John M.; Ness, Norman F., A model of interplanetary and coronal magnetic fields, Solar Physics,6,442-455,1969.
Scherrer, P. H.; Bogart, R. S.; Bush, R. I.; Hoeksema, J. T.; Kosovichev, A. G.; Schou, J.; Rosenberg, W.; Springer, L.; Tarbell, T. D.; Title, A.; Wolfson, C. J.; Zayer, I.; MDI Engineering Team, The Solar Oscillations Investigation-Michelson Doppler Imager, Solar Physics,162,129-188,1995.
Schwenn, R., Solar Wind Sources and Their Variations Over the Solar Cycle,124,51-76,2006. Shen, Chenglong; Wang, Yuming; Ye, Pinzhong; Wang, S., Is There Any Evident Effect of Coronal Holes on Gradual Solar Energetic Particle Events?, The Astrophysical Journal.639,510-515,2006.
Strachan, L.; Suleiman, R.; Panasyuk, A. V.; Biesecker. D. A.; Kohl, J. L., Empirical Densities, Kinetic Temperatures, and Outflow Velocities in the Equatorial Streamer Belt at Solar Minimum, The Astrophysical Journal,571,1008-1014,2002.
Tsurutani, Bruce T.; Gonzalez, Walter D.; Gonzalez, Alicia L. C.; Guarnieri, Fernando L.; Gopalswamy, Nat; Grande, Manuel; Kamide, Yohsuke; Kasahara, Yoshiya; Lu, Gang; Mann, Ian; McPherron, Robert; Soraas, Finn; Vasyliunas, Vytenis, Corotating solar wind streams and recurrent geomagnetic activity:A review. Journal of Geophysical Research,111, A07S01,2006.
Vrsnak, Bojan; Temmer, Manuela; Veronig, Astrid M., Coronal Holes and Solar Wind High-Speed Streams:Ⅱ. Forecasting the Geomagnetic Effects,Solar Physics,240,331-346,2007.
Wang,Y.-M, Coronal Holes and Open Magnetic Flux, Space Science Reviews,144,383-399,2009
Wilcox, John M., The Interplanetary Magnetic Field. Solar Origin and Terrestrial Effects, Space Science Reviews,8,258-328,1968.
Xia, L. D.; Marsch, E.; Curdt, W., On the outflow in an equatorial coronal hole, Astronomy and Astrophysics,399, L5-L9,2003.
Y.-M. Wang;N.R.Sheeley,Jr., Solar wind speed and coronal flux-tube expansion, Astrophysical Journal,355,726-732,1990.
Y.-M. Wang;N.R.Sheeley,Jr.,The solar wind and its magnetic sources at sunspot maximum, The Astrophysical Journal,587,818-822,2003.
Zhang, Jun; Zhou, Guiping; Wang, Jingxiu; Wang, Haimin, Magnetic Evolution and Temperature Variation in a Coronal Hole, The Astrophysical Journal,655,L113-L116,2007.
Zhao, Xuepu; Hoeksema, J. Todd,Prediction of the interplanetary magnetic field strength, Journal of Geophysical Research,100,19-33,1995.
Zirker, J. B., Coronal holes and high-speed wind streams, Reviews of Geophysics and Space Physics,15,257-269,1977.
林元章,太阳物理导论,2000
刘振兴等,太空物理学,2005
章振大,日冕物理,2000
Arge, Charles N.; Odstrcil, Dusan; Pizzo, Victor J.; Mayer, Leslie R., Improved Method for Specifying Solar Wind Speed Near the Sun. SOLAR WIND TEN: Proceedings of the Tenth International Solar Wind Conference. AIP Conference Proceedings,679,190-193,2003.
Biermann, L., Kometenschweife und solare Korpuskularstrahlung, Zeitschrift fur Astrophysik,29,274,1951.
Chertok, I. M.; Obridko, E. I.; Mogilevsky, V. N.; Shilova, N. S.; Hudson, H. S., Solar Disappearing Filament Inside a Coronal Hole, The Astrophysical Journal,567,1225-1233,2002.
Cranmer, S. R., Why is the Fast Solar Wind Fast and the Slow Solar Wind Slow? (Invited) A Survey of Geometrical Models, Proceedings of the Solar Wind 11/SOHO 16, "Connecting Sun and Heliosphere" Conference,159,2005.
Cranmer, Steven R., Coronal Holes, Living Reviews in Solar Physics, vol.6, no. 3,2009.
DeForest, C. E.; Lamy, P. L.; Llebaria, A., Solar Polar Plume Lifetime and Coronal Hole Expansion:Determination from Long-Term Observations, The Astrophysical Journal,560,490-498,2001.
E.Marsch,Solar wind models from the sun to 1 AU:constraints by in situ and remote sensing measurements,Space Science Reviews,87,1-24,1999.
Fisher, Richard; Guhathakurta, Madhulika, Physical Properties of Polar Coronal Rays and Holes as Observed with the SPARTAN 201-01 Coronagraph, Astrophysical Journal Letters,447,L139,1995.
Gonzalez, W. D., B. T. Tsurutani, and A. L. Clua de Gonzalez,Interplanetary origin of geomagnetic storms, Space Sci. Rev.,88,529-562.,1999.
Habbal, Shadia Rifai; Woo, Richard, Connecting the Sun and the Solar Wind: Comparison of the Latitudinal Profiles of Coronal and Ulysses Measurements of the Fast Wind, The Astrophysical Journal,549,L253-L256,2001.
Hansteen, Viggo H.; Leer, Egil, Coronal heating, densities, and temperatures and solar wind acceleration. Journal of Geophysical Research,100,21577-21594,1995.
Hundhausen, A. J., An interplanetary view of coronal holes, Coronal holes and high speed wind streams,225-329,1977.
Kivelson,M.G.,Russell,C.T.,Introduction to Space Physics,91,1995.
Krieger, A. S.; Timothy, A. F.; Roelof, E. C., A Coronal Hole and Its Identification as the Source of a High Velocity Solar Wind Stream,Solar Physics,29,505-525,1973.
Luo, Bingxian; Zhong, Qiuzhen; Liu, Siqing; Gong, Jiancun, A New Forecasting Index for Solar Wind Velocity Based on EIT 284 (?) Observations, Solar Physics,250,159-170,2008.
Moses, D.; Clette, F.; Delaboudiniere, J.-P.; Artzner, G. E.; Bougnet, M.; Brunaud, J.; Carabetian, C.; Gabriel, A. H.; Hochedez, J. F.; Millier, F.; Song, X. Y.; Au, B.; Dere, K. P.; Howard, R. A.; Kreplin, R.; Michels, D. J.; Defise, J. M.; Jamar, C.; Rochus, P.; Chauvineau, J. P.; Marioge, J. P.; Catura, R. C.; Lemen, J. R.; Shing, L.; Stern, R. A.; Gurman, J. B.; Neupert, W. M.; Newmark, J.; Thompson, B.; Maucherat, A.; Portier-Fozzani, F.; Berghmans, D.; Cugnon, P.; van Dessel, E. L.; Gabryl, J. R., EIT Observations of the Extreme Ultraviolet Sun, Solar Physics,175,571-599,1997.
Munro, R. H.; Jackson, B. V., Physical properties of a polar coronal hole from 2 to 5 solar radii, Astrophysical Journal,213,874,875,877-886,1977.
Neugebauer,Marcia;Snyder,Conway,W.,SolarPlasma Experiment,Science,138,1095-1097,1962. Noci, Giancarlo, Energy Budget in Coronal Holes, Solar Physics,28,403-407,1973.
Parker,E.N., Dynamics of the Interplanetary Gas and Magnetic Fields, Astrophysical Journal,128,664,1958.
Riley, Pete; Linker, J. A.; Mikic, Z.; Lionello, R.; Ledvina, S. A.; Luhmann, J. G., A Comparison between Global Solar Magnetohydrodynamic and Potential Field Source Surface Model Results, The Astrophysical Journal,653,1510-1516,2006.
Robbins, S.; Henney, C. J.; Harvey, J. W., Solar Wind Forecasting with Coronal Holes, Solar Physics,233,265-276,2006.
Schatten, Kenneth H.; Wilcox, John M.; Ness, Norman F., A model of interplanetary and coronal magnetic fields, Solar Physics,6,442-455,1969.
Scherrer, P. H.; Bogart, R. S.; Bush, R. I.; Hoeksema, J. T.; Kosovichev, A. G.; Schou, J.; Rosenberg, W.; Springer, L.; Tarbell, T. D.; Title, A.; Wolfson, C. J.; Zayer, I.; MDI Engineering Team, The Solar Oscillations Investigation-Michelson Doppler Imager, Solar Physics,162,129-188,1995.
Schwenn, R., Solar Wind Sources and Their Variations Over the Solar Cycle,124,51-76,2006. Shen, Chenglong; Wang, Yuming; Ye, Pinzhong; Wang, S., Is There Any Evident Effect of Coronal Holes on Gradual Solar Energetic Particle Events?, The Astrophysical Journal.639,510-515,2006.
Strachan, L.; Suleiman, R.; Panasyuk, A. V.; Biesecker. D. A.; Kohl, J. L., Empirical Densities, Kinetic Temperatures, and Outflow Velocities in the Equatorial Streamer Belt at Solar Minimum, The Astrophysical Journal,571,1008-1014,2002.
Tsurutani, Bruce T.; Gonzalez, Walter D.; Gonzalez, Alicia L. C.; Guarnieri, Fernando L.; Gopalswamy, Nat; Grande, Manuel; Kamide, Yohsuke; Kasahara, Yoshiya; Lu, Gang; Mann, Ian; McPherron, Robert; Soraas, Finn; Vasyliunas, Vytenis, Corotating solar wind streams and recurrent geomagnetic activity:A review. Journal of Geophysical Research,111, A07S01,2006.
Vrsnak, Bojan; Temmer, Manuela; Veronig, Astrid M., Coronal Holes and Solar Wind High-Speed Streams:Ⅱ. Forecasting the Geomagnetic Effects,Solar Physics,240,331-346,2007.
Wang,Y.-M, Coronal Holes and Open Magnetic Flux, Space Science Reviews,144,383-399,2009
Wilcox, John M., The Interplanetary Magnetic Field. Solar Origin and Terrestrial Effects, Space Science Reviews,8,258-328,1968.
Xia, L. D.; Marsch, E.; Curdt, W., On the outflow in an equatorial coronal hole, Astronomy and Astrophysics,399, L5-L9,2003.
Y.-M. Wang;N.R.Sheeley,Jr., Solar wind speed and coronal flux-tube expansion, Astrophysical Journal,355,726-732,1990.
Y.-M. Wang;N.R.Sheeley,Jr.,The solar wind and its magnetic sources at sunspot maximum, The Astrophysical Journal,587,818-822,2003.
Zhang, Jun; Zhou, Guiping; Wang, Jingxiu; Wang, Haimin, Magnetic Evolution and Temperature Variation in a Coronal Hole, The Astrophysical Journal,655,L113-L116,2007.
Zhao, Xuepu; Hoeksema, J. Todd,Prediction of the interplanetary magnetic field strength, Journal of Geophysical Research,100,19-33,1995.
Zirker, J. B., Coronal holes and high-speed wind streams, Reviews of Geophysics and Space Physics,15,257-269,1977.
林元章,太阳物理导论,2000
刘振兴等,太空物理学,2005
章振大,日冕物理,2000