1 00:00:00,050 --> 00:00:04,080 Waves 2 00:00:16,150 --> 00:00:08,080 Music 3 00:00:16,170 --> 00:00:20,210 Narrator: Everywhere we look in nature, patterns repeat themselves. The curl of a surfing wave, for example, 4 00:00:20,230 --> 00:00:24,220 is mirrored in clouds and on other planets like saturn, 5 00:00:24,240 --> 00:00:28,270 and now they've been spotted in the sun's atmosphere. This shape of wave is often 6 00:00:28,290 --> 00:00:32,300 formed by something called a Kelvin-Helmholtz, or K-H, instability, in which two 7 00:00:32,320 --> 00:00:36,330 fluids flow by each other with different speeds or densities. Leon Ofman: For in example in clouds, 8 00:00:36,350 --> 00:00:40,360 you have one layer where there is a cloud, 9 00:00:40,380 --> 00:00:44,400 and then a higher layer where you have a jet 10 00:00:44,420 --> 00:00:48,420 stream. So at the boundary between these two regions you start seeing 11 00:00:48,440 --> 00:00:52,480 this cloud rolling up. If you look at water waves, the wind will sort-of 12 00:00:52,500 --> 00:00:56,510 cause it to roll-up into a bigger and bigger wave, but eventually 13 00:00:56,530 --> 00:01:00,560 this wave will break. This is very similar to the Kelvin-Helmholtz instability 14 00:01:00,580 --> 00:01:04,610 that takes place on the sun, where we have erupting plasma 15 00:01:04,630 --> 00:01:08,650 and we have stationary plasmas. Narrator: Spotting a repeating pattern like this is always 16 00:01:08,670 --> 00:01:12,700 good news. Since scientists already know that the movement of the waves transfers energy 17 00:01:12,720 --> 00:01:16,750 to the water, they know that the same thing should be happening in the sun. 18 00:01:16,770 --> 00:01:20,810 That extra energy helps explain how the sun's atmosphere, or corona, heats up to some 19 00:01:20,830 --> 00:01:24,840 1,000 times hotter than the sun's surface. These waves were spotted in the 20 00:01:24,860 --> 00:01:28,860 second coronal mass ejection, or CME, recorded by the Solar Dynamics Observatory 21 00:01:28,880 --> 00:01:32,910 which began looking at the sun in March 2010. Leon Ofman: We were able 22 00:01:32,930 --> 00:01:36,940 to see as the CME erupted 23 00:01:36,960 --> 00:01:40,950 it generated basically a region where the plasma was evacuated. Since 24 00:01:40,970 --> 00:01:44,980 the material from the CME lifted up into space, we see 25 00:01:45,000 --> 00:01:49,000 a dark region that corresponds to the low density 26 00:01:49,020 --> 00:01:53,040 region evacuated by the CME and we see just 27 00:01:53,060 --> 00:01:57,060 adjacent to it a brighter region where we have denser plasma. 28 00:01:57,080 --> 00:02:01,110 So, now, we see a region where the vortices start to roll-up. 29 00:02:01,130 --> 00:02:05,140 Narrator: Astronomers have long thought that turbulence in the corona might help heat it up, 30 00:02:05,160 --> 00:02:09,160 but solar observations still can't see the way the atmosphere moves at small scales. 31 00:02:09,180 --> 00:02:13,200 Each of the rolling surfing waves spotted by SDO was about the size of the United 32 00:02:13,220 --> 00:02:17,240 States. And they likely became more and more turbulent the same way that a breaking water 33 00:02:17,260 --> 00:02:21,280 wave froths at its crest. Leon Ofman: So it is a way of taking out the energy 34 00:02:21,300 --> 00:02:25,340 from the shear flow and converting it, eventually, into heat. 35 00:02:25,360 --> 00:02:29,370 Narrator: Some scientists thought that the sun's powerful magnetic fields would prevent 36 00:02:29,390 --> 00:02:33,410 K-H waves from forming, so the heliophysicists who observed the turbulence on the sun 37 00:02:33,430 --> 00:02:37,450 needed additional evidence. Leon Ofman: To support this interpretation, we also developed 38 00:02:37,470 --> 00:02:41,490 a model, a computational-numerical model. We set up 39 00:02:41,510 --> 00:02:45,520 this model to resemble what takes place in this region, 40 00:02:45,540 --> 00:02:49,560 and we see that, indeed, this kind of shear can form 41 00:02:49,580 --> 00:02:53,580 Kelvin-Helmholtz instability and generate the waves that are similar to 42 00:02:53,600 --> 00:02:57,610 the waves we observe in nature. Narrator: A good surfer understands 43 00:02:57,630 --> 00:03:01,640 those waves intuitively. Thankfully, scientists understand them physically too. 44 00:03:01,660 --> 00:03:05,660 Watching how they roll around the sun opens the door for more research and better solar 45 00:03:05,680 --> 00:03:09,700 models, helping scientists predict the activity of the star we live with.