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Post by af4ex on Oct 30, 2010 13:12:54 GMT
What about Lang's observations of 'dramatic' changes in polarization prior to a flare. Why aren't these features used to predict flares today?
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Post by lsvalgaard on Oct 30, 2010 14:35:04 GMT
What about Lang's observations of 'dramatic' changes in polarization prior to a flare. Why aren't these features used to predict flares today? because they did not hold up over time = not reliable predictor |
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Post by csspider57 on Nov 2, 2010 19:24:19 GMT
Been out doing some space truckin on the net when I ran into Janet Luhmann at the AGU 2009 in SF. (on video that is) She really blew my socks off. Are you familiar with her works and would you welcome questions from ah ah ..understanding about how the current solar wind is mostly being generated by its surface field and not its dipolar field? Her short presentation was; Mapping the Sun's Atmosphere Into Interplanetary Space:How recent changes in the solar dynamo are affecting the solar wind around us Luhmans portion begins at about 48:24 min. into the Video. www.agu.org/meetings/fm09/lectures/lecture_videos/U34A.shtml |
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Post by lsvalgaard on Nov 2, 2010 20:24:31 GMT
Been out doing some space truckin on the net when I ran into Janet Luhmann at the AGU 2009 in SF. (on video that is) She really blew my socks off. Are you familiar with her works and would you welcome questions from ah ah ..understanding about how the current solar wind is mostly being generated by its surface field and not its dipolar field? Her short presentation was; Mapping the Sun's Atmosphere Into Interplanetary Space:How recent changes in the solar dynamo are affecting the solar wind around us Luhmans portion begins at about 48:24 min. into the Video. www.agu.org/meetings/fm09/lectures/lecture_videos/U34A.shtmlYes, I know Janet well. It has always [last 35 years] been understood that the solar wind comes from all over the surface and not just the poles. What we see in the interplanetary medium is a mixture of the two. This is not a change in the solar dynamo. |
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Post by france on Nov 4, 2010 10:02:34 GMT
On Carla thread I asked for you
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Post by lsvalgaard on Nov 4, 2010 17:11:07 GMT
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Post by france on Nov 4, 2010 21:36:12 GMT
ok I'll read your analysis. May be their calculations were wrong but there is a relation (equation) to find with magnetism (indice aa) and solar emissions (ssn) my graph shows that.  So I understand you think "open solar flux" isn't a valide scientific notion ? Edit : I've just read one paper but I see you speak about HMF what I used is "aa index" it's not the same (and Lockwood took "indice aa" too in his formula, you don't ?) I read the begining of the first link I see where is the error but the graph I made concerns 1950-2000 period your curves are correct for this period. Your matter concern the doubling of Sun’s Coronal Magnetic Field, I understand you find an error. But I would like to know if "open solar flux" and its equation scientific are good values ? like it's developed here www.eiscat.rl.ac.uk/Members/mike/publications/pdfs/2003/213_Lockwood_2002JA009431.pdf |
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Post by lsvalgaard on Nov 4, 2010 23:27:09 GMT
ok I'll read your analysis. May be their calculations were wrong but there is a relation (equation) to find with magnetism (indice aa) and solar emissions (ssn) my graph shows that. So I understand you think "open solar flux" isn't a valide scientific notion ? Edit : I've just read one paper but I see you speak about HMF what I used is "aa index" it's not the same (and Lockwood took "indice aa" too in his formula, you don't ?) I read the begining of the first link I see where is the error but the graph I made concerns 1950-2000 period your curves are correct for this period. Your matter concern the doubling of Sun’s Coronal Magnetic Field, I understand you find an error. But I would like to know if "open solar flux" and its equation scientific are good values ? like it's developed here www.eiscat.rl.ac.uk/Members/mike/publications/pdfs/2003/213_Lockwood_2002JA009431.pdfFrom the open flux [or the interplanetary magnetic field] one can calculate aa. And it works in reverse too, if one does it right. To be very precise, aa = 1/6 * B * (v/100)^2, where B is the interplanetary [or heliospheric] magnetic field in nanoTesla and V is the solar wind speed in kilometer per second. So, if B = 10 nT and V = 500 km/sec, aa = 42. This holds on average, if B is pointing south, aa will be larger, if B is pointing north, B will be smaller, but on average the formula works well. Now, when there are many sunspots, B will tend to be larger, so aa will be larger too when ssn is high. |
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Post by rangertab1 on Nov 5, 2010 19:35:37 GMT
Is this measurement (nanoTesla) based off our understanding of magnetohydrodynamics?
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Post by france on Nov 5, 2010 23:11:32 GMT
From the open flux [or the interplanetary magnetic field] one can calculate aa. And it works in reverse too, if one does it right. To be very precise, aa = 1/6 * B * (v/100)^2, where B is the interplanetary [or heliospheric] magnetic field in nanoTesla and V is the solar wind speed in kilometer per second. So, if B = 10 nT and V = 500 km/sec, aa = 42. This holds on average, if B is pointing south, aa will be larger, if B is pointing north, B will be smaller, but on average the formula works well. Now, when there are many sunspots, B will tend to be larger, so aa will be larger too when ssn is high. thanks very much Dr Svalgaard, is it your own equation or from someone else ? You make your prevision of solar cycle with IMF if I'm not wrong. what represent 1/6 ? |
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Post by lsvalgaard on Nov 6, 2010 1:28:21 GMT
From the open flux [or the interplanetary magnetic field] one can calculate aa. And it works in reverse too, if one does it right. To be very precise, aa = 1/6 * B * (v/100)^2, where B is the interplanetary [or heliospheric] magnetic field in nanoTesla and V is the solar wind speed in kilometer per second. So, if B = 10 nT and V = 500 km/sec, aa = 42. This holds on average, if B is pointing south, aa will be larger, if B is pointing north, B will be smaller, but on average the formula works well. Now, when there are many sunspots, B will tend to be larger, so aa will be larger too when ssn is high. thanks very much Dr Svalgaard, is it your own equation or from someone else ? You make your prevision of solar cycle with IMF if I'm not wrong. what represent 1/6 ? This is basically my own equation [based on the papers I referenced], but is generally agreed upon as a good approximation. The '1/6' is just a calibration factor to have the result come out in aa-units. The prediction of the solar cycle is made from the polar fields of the sun which is only weakly and indirectly related to aa. |
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Post by Bob k6tr on Nov 6, 2010 6:36:43 GMT
Leif.....just an FYI
I don't know if this is of any signficance to you. The 27 day Solar Rotation has bottommed out at a Sunspot count of 17. According to the STAR Website this is the first time this Cycle where the bottom of the 27 Day Cycle is above 0.
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Post by france on Nov 6, 2010 10:26:29 GMT
thanks very much Dr Svalgaard, is it your own equation or from someone else ? You make your prevision of solar cycle with IMF if I'm not wrong. what represent 1/6 ? This is basically my own equation [based on the papers I referenced], but is generally agreed upon as a good approximation. The '1/6' is just a calibration factor to have the result come out in aa-units. The prediction of the solar cycle is made from the polar fields of the sun which is only weakly and indirectly related to aa. So triple "thanks" I consider myself very honoured  I don't remember if you gave formula you use for to predict solar cycles |
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Post by lsvalgaard on Nov 6, 2010 16:19:33 GMT
This is basically my own equation [based on the papers I referenced], but is generally agreed upon as a good approximation. The '1/6' is just a calibration factor to have the result come out in aa-units. The prediction of the solar cycle is made from the polar fields of the sun which is only weakly and indirectly related to aa. So triple "thanks" I consider myself very honoured I don't remember if you gave formula you use for to predict solar cycles it is in here www.leif.org/research/Cycle%2024%20Smallest%20100%20years.pdf |
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Post by austinq on Nov 6, 2010 17:59:48 GMT
Hello Dr. lsvalgaard, Pardon me is this question could require some archive searching, but I would be interested in knowing the amount of solar activity during the days preceding and following Sept. 11, 2001, and specifically, their influence on Earth (and the geomagnetic field, of course). Thanks in advance for the answer. |
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