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1.
Rev Sci Instrum ; 94(8)2023 Aug 01.
Article in English | MEDLINE | ID: mdl-38065134

ABSTRACT

We present the design and absolute calibration of a charged particle online readout CMOS system tailored for high-power laser experiments. This system equips a Thomson parabola spectrometer, which is used at the Apollon petawatt scale laser facility to measure the spectra of protons produced by high-intensity laser-target interactions. The RadEye1 CMOS matrices array detectors are paired with a custom triggering system for image grabbing. This allows us to register the proton and ion signals remotely. The repetition rate is presently 1 shot/min, but the frame grabbing enables the system to be compatible with modern high-power lasers running, e.g., at 1 Hz. We detail here the implementation, in the harsh electromagnetic environment of such interactions, of the system, and its absolute calibration, which was performed for proton energies from 4 to 20 MeV.

2.
Phys Rev Lett ; 130(26): 265101, 2023 Jun 30.
Article in English | MEDLINE | ID: mdl-37450828

ABSTRACT

The propagation and energy coupling of intense laser beams in plasmas are critical issues in inertial confinement fusion. Applying magnetic fields to such a setup has been shown to enhance fuel confinement and heating. Here we report on experimental measurements demonstrating improved transmission and increased smoothing of a high-power laser beam propagating in a magnetized underdense plasma. We also measure enhanced backscattering, which our kinetic simulations show is due to magnetic confinement of hot electrons, thus leading to reduced target preheating.


Subject(s)
Electrons , Heating , Heart Rate , Kinetics , Lasers
3.
Ann Ig ; 34(6): 619-626, 2022.
Article in English | MEDLINE | ID: mdl-35060993

ABSTRACT

Background: Heart failure affects about 64 million people worldwide, and despite the economic resources employed to improve its prognosis, mortality is still alarming. The aim of this study was to investigate the impact of patients' characteristics on survival probability during one-year follow-up after an index hospitalization for heart failure. Study design: A three-year retrospective study was conducted on the records of the Hospitals belonging the Local Health Unit of L'Aquila, a Healthcare Facility located in the centre of Italy. Methods: Patients admitted to hospital with a heart failure event as main diagnosis were selected and followed up for one year after their discharge to obtain data for survival analysis. Results: During the observational period for 1,929 patients hospitalized with a Heart failure index event, 1,655 (85.8%) of them were discharged alive and followed up for one year after the discharge. Fourteen percent of patients (n = 232) died for reasons related to Heart failure during the follow-up period. Fifty percent of them (n = 116), died within three months from the index hospitalization discharge. Age ≥75 years (HR 3.192, 95% CI 1.964-5.188), discharging to home (HR 0.399, 95% CI 0.297-0.536), length of stay ≥8 days during the index hospitalization (HR 1.533, 95% CI 1.163-2.019), and high education level (HR 0.517, 95% CI 0.273-0.977), were found to be associated with the survival probability. Conclusion: Study results indicate that older patients, especially those with a low educational level, those with longer index hospitalization, and those not sent directly to home, deserve more care and attention after discharge.


Subject(s)
Heart Failure , Hospitalization , Aged , Follow-Up Studies , Heart Failure/therapy , Humans , Italy , Probability , Retrospective Studies
4.
Ann Ig ; 34(5): 439-452, 2022.
Article in English | MEDLINE | ID: mdl-35060994

ABSTRACT

Background: The body art (tattoos, body piercing and other aesthetic practices) is increasing at global level and involves different aspects of public health, from epidemiological feature to cultural and psychosocial determinants and regulatory issues. The study is aimed at estimating the prevalence of tattooed and pierced in youth, focusing on emerging profiles. Study design: A cross-sectional study has been conducted on 575 students at the first year of degree courses of an Italian University. Methods: Students were asked to fill an online questionnaire. Logistic regression models were evaluated in order to identify predictive factors and determinants of practice (tattoos, piercing, body art). Results: The 41.9% of participants underwent at least one body art intervention, with a higher prevalence in females. Multivariate logistic regression suggested an association of body art practice with type of school and university course, as well as lifestyle characteristics (smoking, alcohol abuse). In addition, the intention to undergo to body art intervention in the future appeared significantly higher in women and more frequent in apparently 'protected' categories such as medical students and non-problematic alcohol users. Conclusions: The study confirmed the importance of the surveillance and social and behavioural research on body art practice and suggested different health promotion perspectives, such as early intervention towards adolescents and late intervention towards young adults belonging to lesser risky population groups.


Subject(s)
Body Piercing , Tattooing , Adolescent , Body Piercing/psychology , Cross-Sectional Studies , Female , Health Promotion , Humans , Risk Factors , Surveys and Questionnaires , Tattooing/psychology , Young Adult
5.
J Acoust Soc Am ; 149(2): 758, 2021 02.
Article in English | MEDLINE | ID: mdl-33639779

ABSTRACT

Identifying characteristics of articulatory impairment in speech motor disorders is complicated due to the time-consuming nature of kinematic measures. The goal is to explore whether analysing the acoustic signal in terms of total squared changes of Mel-Frequency Cepstral Coefficients (TSC_MFCC) and its pattern over time provides sufficient spectral information to distinguish mild and moderate dysarthric French speakers with Amyotrophic Lateral Sclerosis (ALS) and Parkinson's Disease (PD) from each other and from healthy speakers. Participants produced the vowel-glide sequences /ajajaj/, /ujujuj/, and /wiwiwi/. From the time course of TSC_MFCCs, event-related and global measures were extracted to capture the degree of acoustic change and its variability. In addition, durational measures were obtained. For both mild and moderately impaired PD and ALS speakers, the degree of acoustic change and its variability, averaged over the complete contour, separated PD and ALS speakers from each other and from healthy speakers, especially when producing the sequences /ujujuj/ and /wiwiwi/. Durational measures separated the moderate ALS from healthy and moderate PD speakers. Using the approach on repetitive sequences targeting the lingual and labial articulators to characterize articulatory impairment in speech motor disorders is promising. Findings are discussed against prior findings of articulatory impairment in the populations studied.


Subject(s)
Dysarthria , Speech Perception , Humans , Speech Acoustics , Speech Intelligibility , Speech Production Measurement
6.
Phys Rev Lett ; 124(13): 135001, 2020 Apr 03.
Article in English | MEDLINE | ID: mdl-32302165

ABSTRACT

A new experimental platform based on laser-plasma interaction is proposed to explore the fundamental processes of wave coupling at the origin of interplanetary radio emissions. It is applied to the study of electromagnetic (EM) emission at twice the plasma frequency (2ω_{p}) observed during solar bursts and thought to result from the coalescence of two Langmuir waves (LWs). In the interplanetary medium, the first LW is excited by electron beams, while the second is generated by electrostatic decay of Langmuir waves. In the present experiment, instead of an electron beam, an energetic laser propagating through a plasma excites the primary LW, with characteristics close to those at near-Earth orbit. The EM radiation at 2ω_{p} is observed at different angles. Its intensity, spectral evolution, and polarization confirm the LW-coalescence scenario.

7.
Ann Ig ; 32(3): 274-284, 2020.
Article in English | MEDLINE | ID: mdl-32266365

ABSTRACT

BACKGROUND: In daily clinical practice, healthcare workers face end-of-life issues, such as futility, which is generally defined as the provision of treatments that do not produce any meaningful benefit for patients. STUDY DESIGN: To investigate the end-of-life issues according to Italian nurses' and physicians' opinions and to detect any differences between them, a secondary analysis of existing data from a cross-sectional study was conducted. METHODS: A validated questionnaire was used involving 351 nurses and 128 physicians from four hospitals in Central Italy. RESULTS: Regarding the definition of futility, nurses mainly focused on agony, suffering, and risks, while physicians paid more attention to the hope of healing. Nevertheless, both were distressed by different aspects of the treatments; in particular, nurses by the 'invasiveness of the treatments' and physicians by the 'over-medicalization of death'. Instead, nurses and physicians similarly recognized patients' right to seek to anticipate the end of life when they are terminally-ill and to express freely their desire not to be revived. CONCLUSIONS: The description of experiences and opinions of health professionals could represent a valid basis to develop a 'regulatory system' aimed to guide and support daily clinical and nursing activities.


Subject(s)
Attitude of Health Personnel , Attitude to Health , Nurses/psychology , Physicians/psychology , Terminal Care , Adult , Aged , Cross-Sectional Studies , Female , Humans , Italy , Male , Middle Aged , Young Adult
8.
Rev Sci Instrum ; 90(6): 063302, 2019 Jun.
Article in English | MEDLINE | ID: mdl-31254995

ABSTRACT

Computational fluid dynamics simulations are performed to design gas nozzles, associated with a 1000 bars backing pressure system, capable of generating supersonic gas jet targets with densities close to the critical density for 1053 nm laser radiation (1021 cm-3). Such targets should be suitable for laser-driven ion acceleration at a high repetition rate. The simulation results are compared to the density profiles measured by interferometry, and characterization of the gas jet dynamics is performed using strioscopy. Proton beams with maximum energies up to 2 MeV have been produced from diatomic hydrogen gas jet targets in a first experiment.

9.
J Am Coll Radiol ; 16(10): 1425-1432, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31103442

ABSTRACT

BACKGROUND: False-positive scans and resultant needless early recalls can increase harms and reduce cost-effectiveness of low-dose CT (LDCT) lung cancer screening. How LDCT scans are interpreted and classified may impact these metrics. METHODS: The Pan-Canadian Early Detection of Lung Cancer risk calculator was used to determine nodule risk of malignancy on baseline screening LDCTs in the Alberta Lung Cancer Screening Study, which were then classified according to Nodule Risk Classification (NRC) categories and ACR Lung Screening Reporting and Data System (Lung-RADS). Test performance characteristics and early recall rates were compared for each approach. RESULTS: In all, 775 baseline screens were analyzed. After a mean of 763 days (±203) of follow-up, lung cancer was detected in 22 participants (2.8%). No statistically significant differences in sensitivity, specificity, or area under the receiver operator characteristic curve occurred between the NRC and Lung-RADS nodule management approaches. Early recall rates were 9.2% and 9.3% for NRC and Lung-RADS, with the NRC unnecessarily recalling some ground glass nodules, and the Lung-RADS recalling many smaller solid nodules with low risk of malignancy. CONCLUSION: Performances of both the NRC and Lung-RADS in this cohort were very good with a trend to higher sensitivity for the NRC. Early recall rates were less than 10% with each approach, significantly lower than rates using the National Lung Screening Trial cutoffs. Further reductions in early recall rates without compromising sensitivity could be achieved by increasing the NRC threshold to 20% for ground glass nodules or by applying the nodule risk calculator with a 5% threshold to 6- to 10-mm solid nodules under Lung-RADS.


Subject(s)
Early Detection of Cancer , Lung Neoplasms/diagnostic imaging , Tomography, X-Ray Computed , Aged , Aged, 80 and over , Alberta/epidemiology , Canada/epidemiology , Data Systems , Female , Humans , Lung Neoplasms/epidemiology , Male , Mass Screening , Middle Aged , Risk Assessment
10.
Phys Rev Lett ; 122(2): 025001, 2019 Jan 18.
Article in English | MEDLINE | ID: mdl-30720299

ABSTRACT

The propagation of fast electron currents in near solid-density media was investigated via proton probing. Fast currents were generated inside dielectric foams via irradiation with a short (∼0.6 ps) laser pulse focused at relativistic intensities (Iλ^{2}∼4×10^{19} W cm^{-2} µm^{2}). Proton probing provided a spatially and temporally resolved characterization of the evolution of the electromagnetic fields and of the associated net currents directly inside the target. The progressive growth of beam filamentation was temporally resolved and information on the divergence of the fast electron beam was obtained. Hybrid simulations of electron propagation in dense media indicate that resistive effects provide a major contribution to field generation and explain well the topology, magnitude, and temporal growth of the fields observed in the experiment. Estimations of the growth rates for different types of instabilities pinpoints the resistive instability as the most likely dominant mechanism of beam filamentation.

11.
Nurse Educ Today ; 70: 115-120, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30179783

ABSTRACT

BACKGROUND: Low academic success rates lead to fewer than the required number of nurses entering the national health systems, impacting on the supply of nurses and with negative consequences for global health care since low nurse-to-patient ratios are associated with an increase of patients' adverse outcomes. OBJECTIVES: This study was mainly aimed at documenting any of the academic outcomes' potential predictors among Nursing Degree Program (NDP) students' characteristics. DESIGN: A retrospective multi-cohort study was conducted. PARTICIPANTS AND SETTING: Ten cohorts of nursing students enrolled in a central Italy university were involved. METHODS: Qualitative and quantitative data on entry characteristics and academic outcomes were retrieved, observing retrospectively 10 cohorts of Italian nursing students for 13 academic years (2004-2017). Multiple regression analyses were conducted to assess if potential predictors reporting a p-value < 0.05 in univariate analyses were independently related to academic outcomes. RESULTS: A total of 2278 students were enrolled in this study. Multivariate analyses showed that 'female gender', 'having attended classical or scientific upper-secondary school', and 'having higher upper-secondary diploma grade' were associated both with the qualitative outcomes (graduation within the legal duration of NDP) and the quantitative ones (final degree exam grade). The weight of the 'admission-test score' in explaining the variance of academic performances was very low (ß = 0.03, 95% CI = 0.01 to 0.05) compared to the 'upper-secondary diploma grade' (ß = 0.14, 95% CI = 0.12 to 0.16). CONCLUSIONS: This evidence should lead to a reflection on the entry-selection methods for NDP, especially in those countries such as Italy, where these methods are essentially based on the entry-test, which in this study was shown to have a very low predictive power for academic outcomes.


Subject(s)
Academic Success , Education, Nursing, Baccalaureate/trends , Students, Nursing/statistics & numerical data , Adult , Female , Humans , Italy , Male , Retrospective Studies , School Admission Criteria , Schools, Nursing
12.
Ann Ig ; 30(3): 200-210, 2018.
Article in English | MEDLINE | ID: mdl-29670989

ABSTRACT

INTRODUCTION: The university educational sphere has many dilemmas. The question of sufficient knowledge and skills for students to acquire abilities to provide care in different clinical setting is one important dilemma. AIM: To measure the level of competencies by nursing students and its application in different clinical environments. METHODS: Nursing students of two Italian universities participated in the research. Data collection took place April to July 2015 using the Nurse Competence Scale. The Strengthening Reporting of Observational Studies in Epidemiology Guidelines was used to describe the study. Pearson's chi-square test, Student's t test, and regression tests were used for statistical analysis. RESULTS: The questionnaire response rate was 87.27% (n = 698). Most of the nursing students assessed their level of competency as 'good' and evaluated themselves as more competent than their actual nursing role. Students also appraised themselves as competent either via their clinical practices accomplished or in the therapeutic interventions. CONCLUSION: This study shows that the self-evaluation of the competencies acquired by nursing students in clinical settings in Latium and Abruzzo is of a good standard. This study also affirms that NCS is a valuable and reliable tool to measure clinical competencies in different clinical settings.


Subject(s)
Clinical Competence , Students, Nursing/psychology , Adult , Cross-Sectional Studies , Educational Measurement , Female , Humans , Italy , Male , Schools, Nursing , Self-Assessment , Surveys and Questionnaires , Young Adult
13.
Ann Ig ; 30(6): 458-469, 2018.
Article in English | MEDLINE | ID: mdl-30614495

ABSTRACT

INTRODUCTION: The Nurse Competence Scale is a tool for evaluating nursing clinical competence. This tool has been used and psychometrically validated previously in different countries but never in Italy. Assessing the validity and reliability of the Nurse Competence Scale in the Italian context has been a strong necessity for many years. AIM: To test the psychometric properties and evaluate the internal construct validity of the Italian version of the Nurse Competence Scale. METHODS: This study is a secondary analysis on a database of 698 bachelor nursing students who were trained in different clinical settings at two Italian universities. Internal consistency was examined with Cronbach's alpha coefficients and inter-item analysis, and construct validity was evaluated by Exploratory Factor Analysis with Oblimin rotation with Kaiser normalization, and eventually Confirmatory Factor Analysis. RESULTS: The results highlighted the necessity for refinements of the Nurse Competence Scale in the Italian Context. The original model of the Nurse Competence Scale (73 items) was not confirmed. The confirmatory factor analysis presented significant values of Chi-squared test = 10942.766, with degrees of freedom being 2.534 and a ratio of χ²/df = 4.318. The Comparative Fit Index value was significant 0.809 and the Normed Fit Index 0.765 was noteworthy too. The value of Root Mean Square Error of Approximation was significant 0.069. The Cronbach's α coefficient for the new scale was excellent (0.922). The exploratory factor analysis resulted in the Italian Nurse Competence Scale composed of 58 items divided into seven dimensions: using the research, professional awareness, ethical values, tutorial functions, professional leadership, educational interventions, and management of care processes. CONCLUSIONS: The Italian version of the Nurse Competence Scale with 7 dimension and 58 items is an appropriate tool for describing and comparing self-assessed competencies by nurses. Such evaluations could constitute an important contribution to have better educational environments. Self-assessment of competencies can also raise a stronger awareness of individual educational needs.


Subject(s)
Clinical Competence , Education, Nursing/standards , Students, Nursing , Adult , Chi-Square Distribution , Clinical Nursing Research , Cross-Sectional Studies , Ethics, Nursing , Factor Analysis, Statistical , Female , Humans , Italy , Leadership , Male , Mentoring , Middle Aged , Nursing Diagnosis/standards , Nursing Process , Principal Component Analysis , Psychometrics , Reproducibility of Results , Self-Assessment , Young Adult
14.
Phys Rev Lett ; 117(1): 015002, 2016 Jul 01.
Article in English | MEDLINE | ID: mdl-27419574

ABSTRACT

This Letter investigates experimentally the backward stimulated Raman scattering (SRS) of two copropagating, 1-µm wavelength, 1.5-ps duration laser pulses focused side by side, but not simultaneously, in a preformed underdense plasma. When the two lasers do not interact, one of the pulses (so-called strong) yields a large SRS reflectivity, while the other weak pulse is essentially ineffective as regards SRS. By contrast, the weak pulse shows significant SRS activity if it is launched in the plasma slightly after the strong one, and for time delays as large as about 15 ps. For crossed polarizations and a lateral distance of 80-90 µm, the time delay has to be larger than 3-4 ps for the weak pulse to be active, while it has just to be positive when the polarizations are parallel. The experimental results are discussed with the help of large-scale particle-in-cell simulations.

15.
Article in English | MEDLINE | ID: mdl-27332424

ABSTRACT

Every day there is a data explosion on the web. In 2013, 5 exabytes of content were created each day. Every hour internet networks carries a quantity of texts equivalent to twenty billion books. For idea Iit is a huge mass of information on the linguistic behavior of people and society that was unthinkable until a few years ago. It is an opportunity for valuable analysis for understanding social phenomena, also in nursing and health care sector.This poster shows the the steps of an idealy strategy for textual statistical analysis and the process of extracting useful information about health care, referring expecially nursing care from journal and web information. We show the potential of web tools of Text Mining applications (DTM, Wordle, Voyant Tools, Taltac 2.10, Treecloud and other web 2.0 app) analyzing text data and information extraction about sentiment, perception, scientific activites and visibility of nursing. This specific analysis is conduct analyzing "Repubblica", first newspaper in Italy (years of analisys: 2012-14) and one italian scientific nursing journal (years: 2012-14).


Subject(s)
Data Mining , Internet , Nursing Research , Humans , Italy
16.
Article in English | MEDLINE | ID: mdl-27332425

ABSTRACT

BACKGROUND: One of the scales most used to measure quickly and easily eHealth Literacy is the eHealth LiteracyScale (eHEALS); however, there was no validation of this scale in Italian. Therefore, the aim of this study was to adapt and validate the eHealth Literacy Scale (eHEALS) to the italian context. METHODS: Italian translation of eHEALS was administered along unit to another two scale for measure lifestyle habits self-esteem and life satisfaction). A sample of 650 university students aged between 18 and 45 years was selected. An exploratory factor analysis, confirmatory factor analysis, analysis of invariance, reliability, stability and bivariate correlations were performed. RESULTS: Exploratory factor analysis revealed a monofactorial structure that explained 67% of variance. Reliability of 0.87 and test-retest correlation of 0.78 was obtained. The questionnaire was invariant by gender. Regarding the criterion validity, a statistically significant and positive correlations between 0.05 and 0.15 with three indicators was obtained (self-esteem, lifestyle habits and life satisfaction). The italian version of the eHEALS tested in this work has shown to be a valid and reliable scale to measure eHealth competence in university students.


Subject(s)
Health Literacy , Telemedicine , Adolescent , Adult , Humans , Italy , Life Style , Middle Aged , Personal Satisfaction , Reproducibility of Results , Self Concept , Students , Surveys and Questionnaires , Translations , Universities , Young Adult
17.
Ann Ig ; 28(1): 58-69, 2016.
Article in English | MEDLINE | ID: mdl-26980510

ABSTRACT

BACKGROUND: The aim of the work presented was to assess job satisfaction of a number of nurses from different departments working in public hospitals in Italy. The assessment was carried out through the combined use of questionnaires, which measured different aspects of job satisfaction, such as coping abilities, stress level and optimism/pessimism. The literature supports the fact that nurses' job dissatisfaction is closely connected with high levels of stress, burnout and physical and mental exhaustion, together with high workload levels and the complexity of care. The growing interest in measuring the levels of nurses' job satisfaction is attributable to a number of problems that have been raised worldwide, two of which are becoming ever so important: turnover and shortage of nurses. The research question is: Which are the main motivating factors of Italian nurses' job satisfaction/dissatisfaction? METHODS: The study used a convenience (non probability) sample of 1,304 nurses from 15 different wards working in Italian public hospitals from a number of cities in northern, central and southern Italy. The survey instrument was a questionnaire consisting of 205 items which included 5 different questionnaires combined together. RESULTS: The results show a low level of job satisfaction (IWS= 11.5, JSS=126.4). However, the participants were overall happy about their job and considered autonomy and salary important factors for job satisfaction. CONCLUSION: Research has shown that the nurses' level of satisfaction in Italian hospitals is low. The results revealed dissatisfaction with task requirements, organizational policies and advance in career. Nurses interviewed did not feel stressed and showed to be optimistic overall. New research on the subject should be conducted by focusing on ward differences, North and South of Italy and on gender differences.


Subject(s)
Burnout, Professional/nursing , Nurse's Role , Personnel Turnover , Workload , Adult , Attitude of Health Personnel , Female , Hospitals, Public , Humans , Interprofessional Relations , Italy/epidemiology , Job Satisfaction , Male , Middle Aged , Personnel Turnover/statistics & numerical data , Salaries and Fringe Benefits/statistics & numerical data , Surveys and Questionnaires , Workload/statistics & numerical data , Workplace/statistics & numerical data
18.
Phys Rev Lett ; 116(7): 075001, 2016 Feb 19.
Article in English | MEDLINE | ID: mdl-26943539

ABSTRACT

Plasma-based laser amplification is considered as a possible way to overcome the technological limits of present day laser systems and achieve exawatt laser pulses. Efficient amplification of a picosecond laser pulse by stimulated Brillouin scattering (SBS) of a pump pulse in a plasma requires to reach the self-similar regime of the strongly coupled (SC) SBS. In this Letter, we report on the first observation of the signatures of the transition from linear to self-similar regimes of SC-SBS, so far only predicted by theory and simulations. With a new fully head-on collision geometry, subpicosecond pulses are amplified by a factor of 5 with energy transfers of few tens of mJ. We observe pulse shortening, frequency spectrum broadening, and down-shifting for increasing gain, signatures of SC-SBS amplification entering the self-similar regime. This is also confirmed by the power law dependence of the gain on the amplification length: doubling the interaction length increases the gain by a factor 1.4. Pump backward Raman scattering (BRS) on SC-SBS amplification has been measured for the first time, showing a strong decrease of the BRS amplitude and frequency bandwidth when SBS seed amplification occurs.

19.
Rev Sci Instrum ; 86(4): 043502, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25933857

ABSTRACT

Ultra-intense lasers can nowadays routinely accelerate kiloampere ion beams. These unique sources of particle beams could impact many societal (e.g., proton-therapy or fuel recycling) and fundamental (e.g., neutron probing) domains. However, this requires overcoming the beam angular divergence at the source. This has been attempted, either with large-scale conventional setups or with compact plasma techniques that however have the restriction of short (<1 mm) focusing distances or a chromatic behavior. Here, we show that exploiting laser-triggered, long-lasting (>50 ps), thermoelectric multi-megagauss surface magnetic (B)-fields, compact capturing, and focusing of a diverging laser-driven multi-MeV ion beam can be achieved over a wide range of ion energies in the limit of a 5° acceptance angle.

20.
Phys Rev Lett ; 113(23): 235001, 2014 Dec 05.
Article in English | MEDLINE | ID: mdl-25526131

ABSTRACT

The intricate spatial and energy distribution of magnetic fields, self-generated during high power laser irradiation (at Iλ^{2}∼10^{13}-10^{14} W.cm^{-2}.µm^{2}) of a solid target, and of the heat-carrying electron currents, is studied in inertial confinement fusion (ICF) relevant conditions. This is done by comparing proton radiography measurements of the fields to an improved magnetohydrodynamic description that fully takes into account the nonlocality of the heat transport. We show that, in these conditions, magnetic fields are rapidly advected radially along the target surface and compressed over long time scales into the dense parts of the target. As a consequence, the electrons are weakly magnetized in most parts of the plasma flow, and we observe a reemergence of nonlocality which is a crucial effect for a correct description of the energetics of ICF experiments.

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