scholarly journals Refraction in Elastic Collisions of Heavy Ions

1984 ◽  
Vol 37 (3) ◽  
pp. 263
Author(s):  
CBO Mohr
Keyword(s):  
Heavy Ions ◽  
Complex Potential ◽  
Heavy Ion ◽  
Angular Distributions ◽  
Wkb Method ◽  
Elastic Collisions

We attempt to improve our understanding of the processes of absorption and refraction in heavy-ion elastic collisions. The WKB method for a complex potential provides a link. The results account for certain observed features of the scattering angular distributions.

scholarly journals Analysis of Angular Distributions of Heavy-ion Inelastic Collisions

1982 ◽  
Vol 35 (1) ◽  
pp. 1
Author(s):  
CBO Mohr
Keyword(s):  
Angular Distribution ◽  
Coulomb Interaction ◽  
Heavy Ions ◽  
Coulomb Excitation ◽  
Heavy Ion ◽  
Inelastic Collisions ◽  
Effective Range ◽  
Transfer Reactions ◽  
Angular Distributions ◽  
Nuclear Excitation

The relative contributions of nuclear and Coulomb excitation to inelastic collisions of heavy ions are examined, and it is shown how to distinguish their effects on the angular distribution. From the experimental distributions for Coulomb excitation it is possible to make an estimate of the effective range of the Coulomb interaction in the collision. The distributions for nuclear excitation are analysed in the same way as in our previous work on transfer reactions, and give very similar results for the greater nuclear penetration in such collisions as compared with elastic collisions.

scholarly journals Carbon?Carbon Elastic Scattering

1962 ◽  
Vol 15 (1) ◽  
pp. 123 ◽  
Author(s):  
PJ Bunyan
Keyword(s):  
Elastic Scattering ◽  
Heavy Ions ◽  
Optical Model ◽  
Heavy Ion ◽  
Angular Distributions ◽  
Preliminary Study

Optical model analyses of elastic scattering of heavy ions have been carried out by Porter (1958) for nitrogen-nitrogen, and a preliminary study of the carbonnitrogen system has been made by Bassel, Melkanoff, and Drisko (Halbert, Hunting, and Zucker 1960). These analyses have shown that the optical model is capable of predicting, to a higher accuracy than the semiclassical models, the heavy ion elastic angular distributions.

scholarly journals Analysis of Angular Distributions of Heavy-ion Transfer Reactions

1980 ◽  
Vol 33 (6) ◽  
pp. 965
Author(s):  
CBO Mohr
Keyword(s):  
Elastic Scattering ◽  
Heavy Ions ◽  
Heavy Ion ◽  
Critical Value ◽  
Transfer Reactions ◽  
Angular Distributions ◽  
Ion Transfer ◽  
S Matrix ◽  
Low Energies ◽  
Nuclear Phases

Proceeding as in our earlier analysis of elastic scattering, but with a form for the S matrix appropriate for transfer, peaked at the critical value Ie and with width parameter .d, it is shown how to analyse the angular distribution of transfer reactions of heavy ions to obtain.d. The effect of the nuclear phases is found not to be of such fundamental importance as in elastic scattering. Analysis of theexperimental data reveals an increase of.d with nuclear size especially at low energies, but an increase of nuclear penetration for transfer collisions of the lightest nuclei. The circumstances in which strong coupling might occur between elastic scattering and transfer are examined.

scholarly journals UV core dimming in coronal streamer belt and the projection effects

2019 ◽  
Vol 623 ◽  
pp. A95 ◽  
Author(s):  
L. Abbo ◽  
S. Giordano ◽  
L. Ofman
Keyword(s):  
Magnetic Structure ◽  
Heavy Ions ◽  
Solar Minimum ◽  
Heavy Ion ◽  
Spectral Lines ◽  
Slow Solar Wind ◽  
Physical Parameters ◽  
Streamer Belt ◽  
Coronal Streamer ◽  
Tilted Dipole

During solar minimum activity, the coronal structure is dominated by a tilted streamer belt, associated with the sources of the slow solar wind. It is known that some UV coronal spectral observations show a quite evident core dimming in heavy ions emission in quiescent streamers. In this paper, our purpose is to investigate this phenomenon by comparing observed and simulated UV coronal ion spectral line intensities. First, we computed the emissivities and the intensities of HI Lyα and OVI spectral lines starting from the physical parameters of a time-dependent 3D three-fluid MHD model of the coronal streamer belt. The model is applied to a tilted dipole (10°) solar minimum magnetic structure. Next, we compared the results obtained from the model in the extended corona (from 1.5 to 4 R⊙) to the UV spectroscopic data from the Ultraviolet Coronagraph Spectrometer (UVCS) onboard SOHO during the minimum of solar activity (1996). We investigate the line-of-sight integration and projection effects in the UV spectroscopic observations, disentangled by the 3D multifluid model. The results demonstrate that the core dimming in heavy ions is produced by the physical processes included in the model (i.e., combination of the effects of heavy ion gravitational settling, and energy exchange of the preferentially heated heavy ions through the interaction with electrons and protons) but it is visible only in some cases where the magnetic structure is simple, such as a (tilted) dipole.

scholarly journals Stopping power of heavy ions in strongly coupled plasmas

1995 ◽  
Vol 13 (2) ◽  
pp. 311-319 ◽  
Author(s):  
G. Zwicknagel ◽  
C. Toepffer ◽  
P.-G. Reinhard
Keyword(s):  
Heavy Ions ◽  
Weak Coupling ◽  
Heavy Ion ◽  
Stopping Power ◽  
Electron Cooling ◽  
Strongly Coupled ◽  
Electron Plasmas ◽  
Coupling Behavior ◽  
Ion Storage ◽  
Coupled Plasmas

We investigate the stopping power of heavy ions in strongly coupled electron plasmas by performing molecular dynamics (MD) computer simulations. A comparison with conventional weak coupling theories shows that these fail in describing the stopping power at low ion velocities and strong coupling. Then nonlinear screening effects become important and this causes a change in the dependence of the stopping power on the ion charge Zp at low ion velocities. From the MD simulation, we find the stopping power to behave like ZP1.43 instead of the weak coupling behavior Zp2 ln(const/Zp). Similar results were recently obtained by experiments in connection with electron cooling at heavy ion storage rings.

scholarly journals Heavy Ion Acceleration at J-PARC

2018 ◽  
Vol 171 ◽  
pp. 21002
Author(s):  
Susumu SATO
Keyword(s):  
High Intensity ◽  
Heavy Ions ◽  
Particle Production ◽  
Heavy Ion ◽  
Proton Accelerator ◽  
Chiral Property ◽  
Region I ◽  
Particle Momentum ◽  
Low Mass ◽  
Frontier Studies

J-PARC, the Japan Proton Accelerator Research Complex, is an accelerator, which provides a high-intensity proton beam. Recently as a very attractive project, the acceleration of heavy ions produced by supplementary ion sources, called J-PARC-HI, is seriously contemplated by domestic as well as international communities. The planned facility would accelerate heavy ions up to U92+ with a beam energy 20 AGeV ([see formula in PDF] of 6.2 AGeV). The highlight of the J-PARC-HI project is its very high beam rate up to ~1011 Hz, which will enable the study of very rare events. Taking advantage of this high intensity, J-PARC-HI will carry out frontier studies of new and rare observables in this energy region: (i) nuclear medium modification of chiral property of vector mesons through low-mass di-lepton signal, (ii) QCD critical pointcharacterization through event-by-event fluctuation signals of particle production, (iii) systematic measurements related to the equation of state through collective flow signal or two-particle momentum correlation signal, or (iv) the search of hyper nuclei with multi strangeness including or exceeding S = 3. The current plan of J-PARC-HI aims to carrying out the first experimental measurements in 2025.

scholarly journals Outflowing protons and heavy ions as a source for the sub-keV ring current

2009 ◽  
Vol 27 (2) ◽  
pp. 839-849 ◽  
Author(s):  
T. T. Giang ◽  
M. Hamrin ◽  
M. Yamauchi ◽  
R. Lundin ◽  
H. Nilsson ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Ring Current ◽  
Particle Interaction ◽  
Heavy Ion ◽  
Local Times ◽  
Cluster Data ◽  
Abstract Data ◽  
Low Altitude ◽  
Field Lines ◽  
Different Characteristics

Abstract. Data from the Cluster CIS instrument have been used for studying proton and heavy ion (O+ and He+) characteristics of the sub-keV ring current. Thirteen events with dispersed heavy ions (O+ and He+) were identified out of two years (2001 and 2002) of Cluster data. All events took place during rather geomagnetically quiet periods. Three of those events have been investigated in detail: 21 August 2001, 26 November 2001 and 20 February 2002. These events were chosen from varying magnetic local times (MLT), and they showed different characteristics. In this article, we discuss the potential source for sub-keV ring current ions. We show that: (1) outflows of terrestrial sub-keV ions are supplied to the ring current also during quiet geomagnetic conditions; (2) the composition of the outflow implies an origin that covers an altitude interval from the low-altitude ionosphere to the plasmasphere, and (3) terrestrial ions are moving upward along magnetic field lines, at times forming narrow collimated beams, but frequently also as broad beams. Over time, the ion beams are expected to gradually become isotropised as a result of wave-particle interaction, eventually taking the form of isotropic drifting sub-keV ion signatures. We argue that the sub-keV energy-time dispersed signatures originate from field-aligned terrestrial ion energising and outflow, which may occur at all local times and persist also during quiet times.

scholarly journals Experimental investigation of ion beam transport in laser initiated plasma channels

2002 ◽  
Vol 20 (4) ◽  
pp. 559-563 ◽  
Author(s):  
D. PENACHE ◽  
C. NIEMANN ◽  
A. TAUSCHWITZ ◽  
R. KNOBLOCH ◽  
S. NEFF ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heavy Ions ◽  
Plasma Channel ◽  
Ion Beam ◽  
Heavy Ion ◽  
High Current ◽  
Beam Transport ◽  
Electrode Gap ◽  
Discharge Gap ◽  
The Magnetic Field

The aim of the presented experiments is to study the transport of a heavy ion beam in a high-current plasma channel. The discharge is initiated in NH3 gas at pressures between 2 and 20 mbar by a line-tuned CO2 laser. A stable discharge over the entire electrode gap (0.5 m) was achieved for currents up to 60 kA. Concerning the ion beam transport, the magnetic field distribution inside the plasma channel has to be known. The ion-optical properties of the plasma channel have been investigated using different species of heavy ions (C, Ni, Au, U) with 11.4 MeV/u during six runs at the Gesellschaft für Schwerionenforschungs-UNILAC linear accelerator. The high magnetic field allowed the accomplishment of one complete betatron oscillation along the discharge channel. The results obtained up to now are very promising and suggest that, by scaling the discharge gap to longer distances, the beam transport over several meters is possible with negligible losses.

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