Solar activity was low. Region 588 (S15W55) produced a C9/1F flare and an associated filament eruption at 11/0419Z. Moderate centimetric radio bursts accompanied this flare including a 920 sfu tenflare. A greater than 10 MeV proton event that began at 11/1135Z is also believed to be associated with this eruption. A CME was observed on LASCO imagery and a preliminary analysis indicates that while most of the ejecta is directed south and west, there is an Earthward directed component. Region 588 is still the only sunspot group on the visible disk and maintains a reverse polarity beta magnetic configuration.

Solar activity is expected to be low to very low. Region 588 may produce isolated C-class flares.

The geomagnetic field was quiet to unsettled. Solar wind speed began the period at elevated levels (over 500 km/s) following yesterday's shock arrival at 10/1925Z. However, IMF Bz stayed predominantly northward and as a result, the geomagnetic disturbance was weak. Solar wind speed dropped to around 430 km/s by the end of the period. A greater than 10 MeV proton event began at 11/1135Z. The peak so far was 35 pfu at 11/1845Z.

The geomagnetic field is expected to range from quiet to minor storm levels. A CME associated with the C2 flare at 09/2040Z is expected to produce occasional active periods on 12 April. Mostly quiet to unsettled conditions are expected on 13 April. Active conditions with high latitude minor storm periods are expected on 14 April in response to today's C9 flare and CME. The greater than 10 MeV proton event in progress now is expected to end on 12 April.

  觀測的       11 Apr 090
  預測的   12 Apr-14 Apr  095/100/105
  90天平均值        11 Apr 109

  觀測的 Afr/Ap 10 Apr  010/010
  估算值     Afr/Ap 11 Apr  010/012
  預測的    Afr/Ap 12 Apr-14 Apr  012/015-010/015-018/025