Speculation about the mysterious origin of the aurora has been around for a long time. But until now, unsubstantiated inferences have been clearly proven. The mystery has been revealed According to a new study published in the journal Nature, a team of physicists from the University of Iowa has finally demonstrated that the aurora is “generated by strong electromagnetic waves during geomagnetic storms.” The Northern Lights appear over a waterfall in Iceland. Photo: Getty Images. Research shows that these phenomena are known as Alfven waves, which launch electrons to Earth, causing the particles to produce a stream of light that scientists call the aurora borealis. “The measurements reveal that the small number of electrons undergo ‘resonant acceleration’ by the electric field of the Alfven wave, similar to a surfer catching a wave and continuing to accelerate while surfing with the wave,” said Deputy Professor Greg Howes, of the Department of Physics and Astronomy at the University of Iowa, is also a co-author of the study, said. The idea that electrons “surf” on an electromagnetic field is a hypothesis first introduced in 1946 by Russian physicist Lev Landau. The theory is named after the physicist who called it Landau damping. After more than 70 years, the Landau damping theory has been proven. Aurora re-creation After decades of research, scientists have understood how the aurora is produced, but only now have they been able to simulate these colorful bands of light. For the first time, artificial auroras have been recreated in the lab using large plasma physics equipment (LPD) at UCLA’s Basic Plasma Science Facility (BaPSF). Auroras observed from the International Space Station. Photo: NASA. According to the CNN , the scientists used a 20-meter-long room to reconstruct the Earth’s magnetic field using powerful magnetic coils on UCLA’s LPD instrument. Inside the room, the scientists created a plasma environment similar to what exists in near-Earth space. “Using a specially designed antenna, we project Alfven waves down the machine, just like when you quickly shake a water hose up and down and watch the waves move along the hose,” Mr Howes said. When they began to experience electrons “surfing” along the wave, they used other specialized instruments to assess how the electrons received energy from the wave. “Although the experiment did not reproduce the range of multicolored light in the sky, our measurements in the laboratory matched predictions from computer simulations and mathematical calculations, demonstrating that the Electrons surfing on Alfven waves can accelerate up to 72 million km / h and create aurora,” Mr Howes said. Study co-author Craig Kletzing added that these experiments allow them to make key measurements to prove the spatial and hypothetical measurements that actually explain how the aurora is produced. The aurora was taken in Alaska. Photo: Getty Images. Many space scientists are also excited by this new news. “I feel so excited! There are very few laboratory experiments that can prove hypotheses and models related to the space environment. Because space is so vast that it can’t be simulated in a lab,” said Patrick Koehn, a scientist in NASA’s Helicopter Physics Division. According to Koehn, understanding the acceleration mechanism of the electrons that produce the aurora will be useful for many future studies. Long road ahead Currently, the theory of how the aurora is generated has been proven, but there is still a long way to go to predict the strength of each upcoming storm. “Predicting the strength of a particular geomagnetic storm, based on observations of the Sun and measurements from spacecraft between the Earth and the Sun, remains a difficult unsolved problem.” Mr Howes said. Howes said they have established the bond of electrons surfing on Alfven waves about more than 16,000 km above the Earth’s surface. And now, they must learn to predict the strength of those Alfven waves using spaceship observatories.

The US has a rather slow 5G rollout. Photo: NetEase Since the advent of 5G technology, US carriers have been slow to deploy 5G networks. The main reasons are limited spectrum resources available for 5G, cumbersome deployment of 5G devices, and lack of killer applications for 5G services. The media often uses words like “fast” to describe 5G speeds, but the speed of 5G wireless network rollout in the US has nothing to do with the word. Over the past three years, the prospect of 5G wireless networks has been the focus of major media reports. But for most Americans, the real 5G that can achieve the desired effect is yet to emerge. Although all the major wireless carriers in the country claim that their 5G services have covered the entire US, industry analysts argue that this so-called 5G service is not much different from the US. 4G. According to market research firm Evercore ISI, most Americans may not enjoy 5G service that is significantly faster than current wireless communication networks. “Overall, it is expected that between late 2021 and late 2023, truly better 5G services will cover two-thirds of the US population,” said James Ratcliffe, an analyst at Evercore ISI. The first batch of mobile phones that support 5G networks was launched in mid-2019, according to Ratcliffe, in the most optimistic scenario, wireless network operators will be able to provide “real” 5G services to 2/3 of the US population in the next 30 months. Meanwhile, the first mobile phone to support 4G network was released in 2010, and the US 4G network was basically rolled out 18 months later. Analysts, academics and former industry executives say a combination of factors has resulted in a relatively slow rollout of 5G networks in the US. Some of these problems are related to network infrastructure: high-speed network transmission frequency bands and signal coverage are limited. Moreover, the new network equipment that needs to be on the shelves to deploy 5G networks is relatively cumbersome. In addition, many new devices are not made in the US, so the time to purchase the device will be longer. Industry observers also point out that the current 5G network still lacks breakthrough applications, and cannot stimulate user demand and promote the spread of services such as mobile video in 4G networks. John Roese, chief technology officer of Dell Technologies and a former executive at companies like Huawei and Nortel, said that although wireless operators have recently invested billions of dollars in 5G networks, when Because their revenue in 5G-related businesses is not stable, they may not be able to accelerate the construction of new networks. According to Mr. Roese, wireless network operators have had disappointing returns when investing in 4G networks. He said that the main beneficiaries of 4G networks are technology companies that provide applications and other services through the network. “So wireless operators are very cautious about this.” Limited frequency range Photo: Sina To meet the large traffic that 5G networks have to transport, carriers need to open “highways” for data. The spectrum is similar to the real estate that the government grants to carriers through auctions to build highways. The more land they have, the more lanes they can open for faster 5G and easier access. Currently, 5G networks mainly transmit data through low-band, mid-band and high-band. High-band (mmWave) aka millimeter wave has the highest data transfer rate and largest bandwidth, but the smallest coverage. Low band has wider coverage but slowest transmission speed. Finally, the mid-band is considered to be the balance between coverage and transmission speed. Companies like Verizon, AT&T, and T-Mobile all claim that their 5G networks now cover more than 200 million Americans, enough to meet US demand. However, most of these networks rely on low-band radio waves to complete coverage, and network transmission speeds are limited. Wireless network operators are currently focused on capturing mid-bands and have invested a lot of money in recent tenders for these resources. But the main problem facing these companies is that most of the mid-band bands have been occupied by US government agencies and other agencies, mainly for military communications and meteorological services. . Until now, wireless network operators could only use a fraction of the mid-band resources. US government agencies are also aware of the lack of mid-band resources. Earlier this year, the US auctioned a total of $81 billion in mid-band licenses, and plans to hold another auction this fall. When operators were preparing to roll out 5G nearly 10 years ago, they generally believed that 5G networks would primarily use high-frequency radio waves, said Stefan Pongratz, analyst at Dell’Oro Group. . This portion of the spectrum resource is essentially unused. But Pangraz says that rolling out a 5G network using millimeter waves requires building more base stations, which will certainly take time to increase deployment density of base stations. He said that until recent years, the US turned its attention to mid-band radio waves as a way to roll out 5G networks faster. Where is the profit point? Photo: Justin Hall Comics Brian Kelley, an associate professor of electrical engineering at the University of Texas at San Antonio, said the lack of disruptive applications is another major factor hindering the rollout of 5G networks. Mr. Kelly, who was an engineer at Motorola, said: “It can be said that this is the biggest factor that can stimulate the speed of 5G deployment.” According to analyst Craig Moffett, the 3 main advantages of 5G networks are faster data transmission (100 times faster than 4G), support for a large number of simultaneous connections, but also significantly improved response speed between devices. device is connected. “There isn’t a single revenue model that can combine these three advantages. It’s not even clear if consumers are willing to pay more for faster video downloads,” Moffett said. Moffitt said that because 5G networks can seamlessly connect sensors and other IoT devices, companies will likely be the first adopters of 5G services. He said that 5G networks “can be considered the next generation of Wi-Fi wireless networks, which are faster, more secure and can connect more devices”. But Moffett said the question is: “Will wireless operators build their own 5G networks for enterprises, or will the enterprises themselves deploy them?” This is important, he says, because if businesses choose to deploy their own 5G networks, wireless operators may lose the associated revenue and not be able to invest more money in building infrastructure. 5G layer. Device problem Currently, in the world, there are 5 companies that have successfully produced network equipment for 5G, none of which is in the US. Photo: Sina 5G networks are very different from 4G, in part because 5G networks need to transmit data at a higher frequency band. This means that upgrading 5G networks requires different technologies and devices. Evercore analyst Ratcliffe says installing new equipment can require finding a suitable location, obtaining the right permits, and even digging up roads and laying fiber optic cables to transfer data at high speeds between base stations. Gazzola, chief executive officer of Atlanta-based infrastructure company Bennett & Pless, said it is expected that by 2022, the construction work needed to bring wireless communication networks to 5G standards will increase. . However, the epidemic and technical obstacles have delayed progress. Equipment availability is also a common issue faced by wireless network operators. Dell’s Rose said that when 4G was first introduced around 2010, there were about a dozen technology vendors offering wireless networking equipment, including Canada’s Nortel and America’s Motorola. Today, there are only five major players in the global network equipment market: Nokia, Ericsson, Samsung, ZTE and Huawei. “Two in China. One in Finland, one in Sweden and one in Korea.” These suppliers are all located outside the US. Worse still, 5G network equipment requires computer chips while the chip industry has been struggling recently to cope with supply shortages.

Xiaoxin Pad Plus has an 11-inch LCD 2K (2000 x 1200) screen, a balanced screen border, an 8MP front camera that supports face unlock because the device does not have a fingerprint sensor. On the back is a 13MP camera with LED flash. The appearance of the machine is also quite simple, the frame is made of plastic, but it can be said that it is not cheap. The device is equipped with Snapdragon 750G processor, comes with 6GB RAM and 128GB ROM. The battery inside has a capacity of 7700mAh, supports Quick Charge 3.0 via Type-C 3.1 port and has a side magnet for charging when using the device in landscape mode. This is also the place to connect to the removable keyboard accessory. Xiaoxin Pad Plus has four JBL 1.5W speakers and Dolby Atmos for surround sound. It also has dual-band Wi-Fi and Bluetooth 5.1 but does not support 5G because there is no SIM slot. The price of the device is only half that of the similarly configured Galaxy Tab S7 FE, specifically $312 compared to the competitor’s $795. But Samsung’s product also has the advantage of a much larger battery, comes with a stylus, but loses because it only has 4GB of RAM and 64GB of ROM. You need to buy separate accessories for Xiaoxin Pad Plus, like a stylus for $47 and a keyboard for $73. In the future, there will also be a removable touchpad and an integrated stand with a hinge that raises the angle from 0° to 165°. According to Gizmochina