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Monday Seminar Talk (short) 17 November, 2003

Monday Seminar Talk (short) 17 November, 2003. Taro Morimoto. Because :. The polar crown filaments need to be removed before the poles could acquire open field structure of the opposite polarity. Abstract. Close Relationship. The solar polarity reversal.

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Monday Seminar Talk (short) 17 November, 2003

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  1. Monday Seminar Talk (short) 17 November, 2003 Taro Morimoto

  2. Because : The polar crown filaments need to be removed before the poles could acquire open field structure of the opposite polarity. Abstract Close Relationship The solar polarity reversal The cessation of high latitude CMEs - based on the observations for cycles 21 & 23.

  3. Goplaswamy et al.(2003) Prominence eruptions at high latitudes subsided around the time of the polarity reversals. (From SOHO/LASCO & NoRH observations) Introduction Disappearance and reformation of polar coronal holes. (Webb, Davis & McIntosh 1984; Bilenko 2002; Harvey & Recely 2002) Disappearance of polar crown filaments(PCF). (Waldmeier 1960; Makarov, Tlatov & Sivaraman 2001)

  4. Data Prominence Eruption (PE) CME 21 Solwind 23 SOHO/LASCO Nobeyama radio heliograph Kitt Peak magnetograph measurements for polar region magnetic field strength Introduction Using CME data of cycles 21 & 23, they tested how CMEs are intimately connected to the mechanism of polarity reversal.

  5. PE and CMEs North-south asymmetry in the high latitude (HL) activities. HCS epochs of cessation of HL activity (north; : south) Max. excursions of heliospheric current sheet. (from Wilcox Obs.) HCS

  6. SSN peak CME peak CME occurence rate HL : High Latitude (≧60°) [PCF-related = 1159 CMEs] LL : Low Latitude (≦40°) [AR-related = 4607 CMEs] SSN: daily Sun Spot Number

  7. month: 03 10 05 10 Polar field reversal: 10/00 from data 02/01 (Bilenko 2002) 05/01 (Durrant & Wilson 2003) PCF disappearance 10/00(Harvey & Recely 2002; Lorenc, Pasorek & Rybansky 2003; Gopalswamy et al. 2003) HL CME peak mid/99 A rapid increase 03/00 – 09/00 A broad maximum South North Cycle 23 Northern HL(NHL) 3s 3s 01 Disappearance of PCF

  8. month: 03 10 05 10 Polar field reversal: 05/01 from data 09/01 (Durrant & Wilson 2003) 01/02 (Bilenko 2002) PCL disappearance 02/02 (Lorenc et al. 2003) 04/02(Harvey & Recely 2002) HL CME peak mid/99– 03/02 South North Cycle 23 Southern HL(SHL) 3s 3s 01 Disappearance of PCF

  9. ② ① Polar field reversal: 02/82- 03/82 (Webb et al.1984) 09/80 & 07/82 from data. PCL disappearance ① Webb et al. 1984 ②Lorenc et al. 2003 HL CME peak light blue shadow region Cycle 21 Northern HL(NHL) 3s 3s South North Disappearance of PCF

  10. Polar field reversal: ② 09/80 (Webb et al. 1984) 02/83 from data. ① PCL disappearance ① Webb et al. 1984 ②Lorenc et al. 2003 HL CME peak (pink shadow region) Cycle 21 Southern HL(SHL) 3s 3s South North Disappearance of PCF

  11. The North-South asymmetry of the polarity reversal time and HL activity is of high importance. The CME process helps the closed field lines overlying PCFs become open to complete the polarity reversal. (c.f.: Low (1997)) Summary The epochs of solar polar reversal are closely related to the cessation of HL CME activities. Before the completion of the reversal, several temporary reversals take place with corresponding spikes in the HL CME rates.

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