To: sisafe Subject: SCP4GM flux vs CXO altitude Date: Thu, 04 Nov 1999 23:29:22 -0500 From: Shanil Virani Good evening all, Some of you are already aware of these plots, however, I thought I would mention it here as well so that everyone else is aware. At http://asc.harvard.edu/acis/radbelt/ you will find two one page plots you may want to print out: logp4vsalt.ps logp4vsaltRe.ps The first plot is a plot of the SCP4GM (EPHIN's lowest energy proton channel, 5 MeV < E < 8.3 MeV) flux vs geocentric radius (in km) for the length of the mission thus far. The second plot is the same as the first except that the altitude is now expressed in terms of Re (I took Re=6378 km). The vertical line drawn in both plots identifies R=60,000 km (~9.4 Re). What these plots demonstrate, however, is that there is a considerable amount of P4 flux out to even 11-12 Re. The implication is that whatever software suite we decide to use in place of the current OFLS model ought to be able to have predictive power to these radii, and greater. No one has mentioned how accurate these various models are as function of distance out to some fiducial radius, so I am suggesting that we keep this in mind when descriminating between various software suites. The one caveat to this analysis is of course is the fact that we really don't know the ~100 keV proton behaviour as a function of altitude, however, we can make inferences based on these plots. Cheers, Shanil To: sisafe Subject: Re: SCP4GM flux vs CXO altitude Date: Fri, 05 Nov 1999 10:08:07 -0500 From: Shanil Virani Hello, > Also, it would be useful for us if you converted the EPHIN raw counts per > integration period to the spectral intensity --- p / (cm^2 sr MeV s). > Thanks. Actually, I did and was available at the web page I cited earlier (http://asc.harvard.edu/acis/radbelt) since last night as well. In my email, I spoke in terms of flux but cited ps files that were in units of counts/int time, I apologise. The files you need to print are: logp4fluxvsalt.ps [now called: SCP4GM vs. Altitude] loge150fluxvsalt.ps [now called: SCP4GM vs. Altitude] where the latter is the same plot as the first except it's the lowest energy electron channel on EPHIN (0.25-0.70 MeV) that is plotted. This channel of course also suffers from detector saturation effects upon entering the belts. This plot may have more utility since if you believe that low energy electrons trace low energy protons, then this plot suggests that EPHIN sees a significant amount of flux out to even ~13Re. Cheers, Shanil ------------------------------------------------------------------------ Shanil N. Virani svirani@head-cfa.harvard.edu Chandra X-ray Observatory Center Harvard-Smithsonian Center for Astrophysics http://hea-www.harvard.edu/~svirani 60 Garden Street, MS-70 FAX: 617-495-7356 Cambridge, MA 02138 USA PHONE: 617-496-7855 "It is not in the stars to hold our destiny but in ourselves." -- William Shakespeare ------------------------------------------------------------------------