اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMethod for estimating charge breeder ECR ion source plasma parameters with short pulse 1+ injection
176
0
0.0
(
0
)
تأليف
J. Angot
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
A new method for determining plasma parameters from beam current transients resulting from short pulse 1+ injection into a Charge Breeder Electron Cyclotron Resonance Ion Source (CB-ECRIS) has been developed. The proposed method relies on few assumptions, and yields the ionisation times $1/n_eleftlanglesigma vrightrangle^{text{inz}}_{qto q+1}$, charge exchange times $1/n_0leftlanglesigma vrightrangle^{text{cx}}_{qto q-1}$, the ion confinement times $tau^q$, as well as the plasma energy contents $n_eleftlangle E_erightrangle$ and the plasma triple products $n_e leftlangle E_erightrangle tau^q$. The method is based on fitting the current balance equation on the extracted beam currents of high charge state ions, and using the fitting coefficients to determine the postdictions for the plasma parameters via an optimisation routine. The method has been applied for the charge breeding of injected K$^+$ ions in helium plasma. It is shown that the confinement times of K$^{q+}$ charge states range from 2.6$^{+0.8}_{-0.4}$ ms to 16.4$^{+18.3}_{-6.8}$ ms increasing with the charge state. The ionisation and charge exchange times for the high charge state ions are 2.6$^{+0.5}_{-0.5}$ ms--12.6$^{+2.6}_{-3.2}$ ms and 3.7$^{+5.0}_{-1.6}$ ms--357.7$^{+406.7}_{-242.4}$ ms, respectively. The plasma energy content is found to be $2.5^{+4.3}_{-1.8}times 10^{15}$ eV/cm$^3$.
قيم البحث
اقرأ أيضاً
The SPIRAL1 charge breeder is now under operation. Radioactive beam has already been delivered [1] to Physicist for performing experiment. Although charge breeding efficiencies demonstrated high performances for stable ion beams, those efficiencies r
egarding radioactive ion beams were found, in the first experiments, lower than expected. The beam optics, prior to the injection of the 1+ ions into the SPIRAL1 charge breeder, is of prime importance [2] for getting such high efficiencies. Moreover, the intensities of the radioactive ion beams are so low, that it is really difficult to tune the charge breeder. The tuning of the charge breeder for radioactive ion beams requires a particular procedure often referred as blind tuning. A stable beam hav-ing a close Brho (few percent) is required to find out the set of optic parameters preceding the tuning of the radioactive beam. Hence, it has been decided to focus our effort on that procedure as to get control of the 1+ beam optics leading to high charge breeding efficiencies whatever the 1+ mass, energy and Target Ion Source System (TISS) used. Being aware that each TISS provide ion beams with a specific energy spread DeltaE, and given that the acceptance energy win-dow of the charge breeder is rather narrow; that parameter must play also an important role in the whole charge breed-ing efficiency.
The local magnetic field in a Penning-Malmberg trap is found by measuring the temperatures that result when electron plasmas are illuminated by microwaves pulses. Multiple heating resonances are observed as the pulse frequencies are swept. The many r
esonances are due to electron bounce and plasma rotation sidebands. The heating peak corresponding to the cyclotron frequency resonance is identified to determine the magnetic field. A new method for quickly preparing low density electron plasmas for destructive temperature measurements enables a rapid and automated scan of microwave frequencies. This technique can determine the magnetic field to high precision, obtaining an absolute accuracy better than $1,mathrm{ppm}$, and a relative precision of $26,mathrm{ppb}$. One important application is in situ magnetometry for antihydrogen-based tests of charge-parity-time symmetry and of the weak equivalence principle
Pulsed and CW operation of negative ion radio frequency surface plasma source with a solenoidal magnetic field is described. Dependences of a beam current on RF power, extraction voltage, solenoid magnetic field, gas flow are presented. Compact design of RF SPS is presented.
The measurement of the axially lost electron energy distribution escaping from a minimum-B electron cyclotron resonance ion source in the range of 4-800 keV is reported. The experiments have revealed the existence of a hump at 150-300 keV energy, con
taining up to 15% of the lost electrons and carrying up to 30% of the measured energy losses. The mean energy of the hump is independent of the microwave power, frequency and neutral gas pressure but increases with the magnetic field strength, most importantly with the value of the minimum-B field. Experiments in pulsed operation mode have indicated the presence of the hump only when microwave power is applied, confirming that the origin of the hump is rf-induced momentum space diffusion. Possible mechanism of the hump formation is considered basing on the quasi-linear model of plasma-wave interaction.
Imposing an external magnetic field in short-pulse intense laser-plasma interaction is of broad scientific interest in related plasma research areas. We propose a simple method using a virtual current layer by introducing an extra current density ter
m to simulate the external magnetic field, and demonstrate it with three-dimensional particle-in-cell simulations. The field distribution and its evolution in sub-picosecond time scale are obtained. The magnetization process takes a much longer time than that of laser-plasma interaction due to plasma diamagnetism arising from collective response. The long-time evolution of magnetic diffusion and diamagnetic current can be predicted based on a simplified analytic model in combination with simulations.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
