http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
<i>SUZAKU</i>/WAM AND<i>RHESSI</i>OBSERVATIONS OF NON-THERMAL ELECTRONS IN SOLAR MICROFLARES
Ishikawa, Shin-nosuke,Krucker, Sä,m,Ohno, Masanori,Lin, Robert P. IOP Publishing 2013 The Astrophysical journal Vol.765 No.2
<P>We report on hard X-ray spectroscopy of solar microflares observed by the Wide-band All-sky Monitor (WAM), on board the Suzaku satellite, and by RHESSI. WAM transient data provide wide energy band (50 keV-5 MeV) spectra over a large field of view (similar to 2 pi sr) with a time resolution of 1 s. WAM is attractive as a hard X-ray solar flare monitor due to its large effective area (similar to 800 cm(2) at 100 keV, similar to 13 times larger than that of RHESSI). In particular, this makes it possible to search for high energy emission in microflares that is well below the RHESSI background. The WAM solar flare list contains six GOES B-class microflares that were simultaneously observed by RHESSI between the launch of Suzaku in 2005 July and 2010 March. At 100 keV, the detected WAM fluxes are more than similar to 20 times below the typical RHESSI instrumental background count rates. The RHESSI and WAM non-thermal spectra are in good agreement with a single power law with photon spectral indices between 3.3 and 4.5. In a second step, we also searched the RHESSI microflare list for events that should be detectable by WAM, assuming that the non-thermal power-law emission seen by RHESSI extends to >50 keV. From the 12 detectable events between 2005 July and 2007 February, 11 were indeed seen by WAM. This shows that microflares, similar to regular flares, can accelerate electrons to energies up to at least 100 keV.</P>
Suzuki, T.,Bhang, H.,Franklin, G.,Gomikawa, K.,Hayano, R.S.,Hayashi, T.,Ishikawa, K.,Ishimoto, S.,Itahashi, K.,Iwasaki, M.,Katayama, T.,Kondo, Y.,Matsuda, Y.,Nakamura, T.,Okada, S.,Outa, H.,Quinn, B. Elsevier 2004 Physics letters: B Vol.597 No.3
<P><B>Abstract</B></P><P>We have measured the proton energy distribution from the <SUP>4</SUP>He(stopped <SUP>K−</SUP>,p) reaction by means of time-of-flight. A mono-energetic peak was observed, which is interpreted as the formation of a new kind of neutral tribaryon S<SUP>0</SUP>(3115) with isospin T=1 and strangeness S=−1. The mass and width of the state were deduced to be 3117.0−4.4+1.5MeV/<SUP>c2</SUP> and <21MeV/<SUP>c2</SUP>, respectively. The state mainly decays into ΣNN.</P>
Search for strange tribaryons in the He4(K<i>stop</i>−,n<sup>π±</sup>) reaction
Yim, H.,Bhang, H.,Chiba, J.,Choi, Seonho,Fukuda, Y.,Hanaki, T.,Hayano, R.S.,Iio, M.,Ishikawa, T.,Ishimoto, S.,Ishiwatari, T.,Itahashi, K.,Iwai, M.,Iwasaki, M.,Kienle, P.,Kim, J.H.,Matsuda, Y.,Ohnishi, Elsevier 2010 Physics letters: B Vol.688 No.1
<P><B>Abstract</B></P><P>We have recently reported on an indication of the strange tribaryon state, S<SUP>+</SUP>, with a mass M∼3140 MeV/<SUP>c2</SUP> and width Γ<23 MeV/<SUP>c2</SUP>, in the neutron time-of-flight (TOF) spectrum of the He4(K<I>stop</I>−,n<SUP>π±</SUP>) reaction of the KEK-PS E471 experiment in a search for the deeply bound narrow <SUP>K−</SUP>ppn (total isospin T=0) state. In an attempt to confirm the state and search for other possible T=0, 1 tribaryonic states, we have re-measured the neutron energy spectrum of the same reaction in the KEK-PS E549 experiment with an upgraded setup for which the TOF resolution was improved 1.5 times and the statistics was increased 6 times. However, in the neutron spectra, we find such a smooth distribution that we conclude the state is either not so strong to stick out of the inclusive background or too broad to be identified as a distinct peak. We estimated the upper limits of the formation probability of the possible tribaryonic state for three widths, 0, 20, and 40 MeV/<SUP>c2</SUP>. The obtained upper limit (95% CL) for a state as narrow as 20 MeV/<SUP>c2</SUP> is at most 1% per stopped kaon over the wide mass range of 3000–3200 MeV/<I>c</I><SUP>2</SUP>, while it reaches to 4∼5% at around 3140 MeV/<I>c</I><SUP>2</SUP> for Γ⩾40 MeV/<SUP>c2</SUP>, implying the possible existence of unknown processes including tribaryonic formation.</P>
Analysis of a PM Motor Drive System by a Coupled Method with MATLAB and FEM
Ishikawa T.,Sunaga T.,Nakamura S.,Mori D.,Hashimoto S.,Matsunami M. The Korean Institute of Electrical Engineers 2005 KIEE International Transactions on Electrical Mach Vol.b5 No.3
Finite element method (FEM) is a very powerful tool for the calculation of magnetic field of electromagnetic devices. MATLAB/Simulink is also well known as a very useful tool for control systems. This paper proposes a very promising method, where the FEM is coupled with MATLAB. We apply this method to analyze a permanent magnet (PM) motor drive system, and compare with results using MATLAB only.
<i>RHESSI</i>IMAGING SURVEY OF γ-RAY BREMSSTRAHLUNG EMISSION IN SOLAR FLARES
Ishikawa, S.,Krucker, Sä,m,Takahashi, T.,Lin, R. P. IOP Publishing 2011 The Astrophysical journal Vol.728 No.1
<P>We present a high-energy (>150 keV) imaging survey of all solar gamma-ray flares observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) to study bremsstrahlung emission from relativistic electrons. Using RHESSI rear segment data, images in the energy range from 150 to 450 keV integrated over the total duration of the impulsive phase of the flare are derived. Out of the 29 gamma-ray peaks in 26 RHESSI flares, we successfully obtained images for 21 gamma-ray peaks in 20 flares. The remaining eight peaks have >150 keV fluences of less than a few hundred photons per cm(2) and counting statistics are too poor for detailed imaging. The flux ratio of the footpoint sources is found to be similar at 50 keV and above 150 keV, indicating that relativistic electrons are present in both footpoints of the flare loop. No correlation between the footpoint separation and the fluence ratio of the 2.2 MeV line and the >300 keV photons is found. This indicates that the relative efficiency of proton to electron acceleration does not depend on loop length, as could have been expected from stochastic acceleration models. As previously reported, the three flares with the best counting statistics show not only footpoint emission, but also a coronal gamma-ray bremsstrahlung source. For events with lower counting statistics, no coronal source could be identified. However, instrumental limitation could easily hide a coronal source for events with lower statistics, suggesting that coronal gamma-ray bremsstrahlung sources are nevertheless a general feature of gamma-ray flares.</P>
ON THE RELATION OF ABOVE-THE-LOOP AND FOOTPOINT HARD X-RAY SOURCES IN SOLAR FLARES
Ishikawa, S.,Krucker, Sä,m,Takahashi, T.,Lin, R. P. IOP Publishing 2011 The Astrophysical journal Vol.737 No.2
<P>We report on the most prominent example of an above-the-loop hard X-ray source in the extensive solar flare database of RHESSI. The limb flare of 2003 October 22 around 20 UT resembles the famous Masuda flare, except that only one of the footpoint sources is visible with the other one occulted. However, even for this very prominent event, the above-the-loop source is only visible during one of the four hard X-ray peaks, highlighting the rare occurrence of above-the-loop sources that are equally bright as footpoint sources. The relative timing between the above-the-loop and footpoint sources shows that the coronal source peaks about 10 s before the footpoint source and decays during the time the footpoint source is most prominent. Furthermore, the derived number of non-thermal electrons within the above-the-loop source is large enough to provide the needed number of precipitating electrons to account for the footpoint emission over the duration of the hard X-ray peak. Hence, these observations support the simple scenario where bulk energization is accelerating all electrons within the above-the-loop source and precipitating electrons are emptying out of the above-the-loop source to produce the footpoint emissions.</P>
Measurements of isospin asymmetry and difference of directCPasymmetries in inclusiveB→Xsγdecays
Watanuki, S.,Ishikawa, A.,Adachi, I.,Aihara, H.,Al Said, S.,Asner, D. M.,Aushev, T.,Ayad, R.,Babu, V.,Badhrees, I.,Bakich, A. M.,Bansal, V.,Behera, P.,Beleñ,o, C.,Berger, M.,Bhardwaj, V.,Bhuyan, American Physical Society 2019 Physical review. D Vol.99 No.3
Precision measurement of the 3d->2p x-ray energy in kaonic <sup>4</sup>He
Okada, S.,Beer, G.,Bhang, H.,Cargnelli, M.,Chiba, J.,Choi, S.,Curceanu, C.,Fukuda, Y.,Hanaki, T.,Hayano, R.S.,Iio, M.,Ishikawa, T.,Ishimoto, S.,Ishiwatari, T.,Itahashi, K.,Iwai, M.,Iwasaki, M.,Juhasz, North-Holland Pub. Co 2007 Physics letters: B Vol.653 No.5
We have measured the Balmer-series x-rays of kaonic <SUP>4</SUP>He atoms using novel large-area silicon drift x-ray detectors in order to study the low-energy K@?-nucleus strong interaction. The energy of the 3d->2p transition was determined to be 6467+/-3(stat)+/-2(syst) eV. The resulting strong-interaction energy-level shift is in agreement with theoretical calculations, thus eliminating a long-standing discrepancy between theory and experiment.